bluuebunny/crossref_metadata_2025 huggingface dataset:
One Health: Insights from Organizational & Social, Technology Assessment and Human Factors Perspectives
Authors: Scott Philip , Kuziemsky Craig , Zhu Xinxin , Nøhr Christian , Ammenwerth Elske , Kukhareva Polina , Peute Linda , Marcilly Romaric
Published: December 2023

Objectives: To offer diverse but complementary perspectives on how biomedical and health informatics can be informed by and help to achieve the vision of One Health.

Methods: Overview of key considerations and critical discussion of common themes, barriers and opportunities, based on collaborative review by International Medical Informatics Association (IMIA) working group members active in related fields.

Results: Health and care systems are complex sociotechnical systems that need explicit design and implementation strategies to align with the goals of One Health. The evidence-based health informatics paradigm and associated frameworks for evaluation of digital health technologies need to broaden their scope to take full account of the One Health approach. Informatics has specific contributions to make to One Health, for example by improved user experience reducing energy consumption and effective app design enhancing medication adherence.

Conclusions: One Health is inherently intertwined with ergonomic, sociotechnical and evaluation perspectives in biomedical and health informatics. Health is a planetary issue that requires interdisciplinary collaborative action. The theories and principles of biomedical and health informatics offer many opportunities to transform digital health technology to better serve the One Health agenda.
Advances in Clinical Decision Support Systems: Contributions from the 2022 Literature
Authors: Lehmann Christoph U. , Subbian Vignesh ,   Section Editors for the IMIA Yearbook Section on Decision Support Systems
Published: December 2023

Objective: To summarize significant research contributions published in 2022 in the field of clinical decision support (CDS) systems and select the best papers for the Decision Support section of the International Medical Informatics Association (IMIA) Yearbook 2023.

Methods: A renewed search query for identifying CDS scholarship was developed using Medical Subject Headings (MeSH) terms and related keywords. The query was executed in PubMed in January 2023. The search results were reviewed in three stages by two reviewers: title-based triaging, followed by abstract screening, and then full text review. The resulting articles were sent for external review to identity best paper candidates.

Results: A total of 1,939 articles related to CDS were retrieved. Of these, 11 articles were selected as candidates for best papers. The general themes of the final three best papers are (1) reducing documentation burden through in-line guidance for clinical notes, (2) clinician engagement for continuous improvement of CDS, and (3) mitigating healthcare-related carbon emissions using scalable and accessible CDS, respectively.

Conclusion: The field of clinical decision support remains highly active and dynamic, with innovative contributions to a range of clinical domains from primary to acute care. Interoperability issues, documentation burden, clinician acceptance, and the need for effective integration into existing healthcare workflows are among the prominent challenges and areas of interest faced by CDS implementation efforts.
Leveraging Data and Technology to Enhance Interdisciplinary Collaboration and Health Outcomes
Authors: Tamburis Oscar , Benis Arriel ,   Section Editors for the IMIA Yearbook Special Topic Section on Informatics for One Health
Published: December 2023

Objective: To give an overview of recent research and propose a selection of best papers published in 2022 in Informatics for One Health.

Methods: An extensive search using PubMed and Web of Science was conducted to identify peer-reviewed articles published between December 2021 and December 2022, in order to find relevant publications in the ‘Informatics for One Health’ field. The selection process comprised three steps: (i) eight candidate best papers were first selected by the two section editors; (ii) external reviewers from internationally renowned research teams reviewed each candidate best paper; and (iii) the editorial committee of the Yearbook conducted the final best paper selection.

Results: The candidate best papers represent studies that characterized significant challenges facing Informatics for One Health. Other trends of interest related to the deployment of medical artificial intelligence tools and the implementation of the FAIR principles within the One Health broad scenario. In general, papers identified in the search fell into one of the following categories: 1) Health improvement via digital technology; 2) Climate change/Environment/Biodiversity; and 3) Maturity of healthcare services.

Conclusion: The topic turns extremely important in the next future for what concerns the need to understand complex interactions in order to safeguard the health of populations and ecosystems.
Optoelectronic properties of the Sb/III-Sb interface induced by laser photooxidation
Authors: Alekseev P. A. , Eliseyev I. A. , Romanov V. V. , Moiseev K. D. , Kunitsyna E. V. , Borodin B. R. , Sharov V. A. , Smirnov A. N. , Davydov V. Yu.
Published: December 2023

Laser photooxidation is used to form a surface antimony layer on p-type GaSb and GaAs0.06Sb0.94. The emerged Sb/III-Sb interface is studied by a combination of the Raman and photoluminescence spectroscopy supported by Kelvin probe microscopy and atomic force microscopy. The laser power density controls the thickness and structure of the Sb layer. Laser photooxidation thickens the amorphous Sb layer that emerged after native oxide formation. The thickening decreases the bandgap photoluminescence intensity and increases surface band bending. Further increase in the laser power density forms a multilayered antimonene phase with a rhombohedral structure. The crystalline Sb layer decreases the surface band bending due to changes in the work function. For the crystalline layer, the PL intensity further decreases. The effective work function model explains the experimental results. Finally, the study shows that it is possible to modify surface optoelectronic properties with a submicrometer lateral resolution.
Enhanced spin Hall effect at high temperature in non-centrosymmetric silicide TaSi2 driven by Berry phase monopoles
Authors: Ishida Ken , Shirokura Takanori , Hai Pham Nam
Published: December 2023

We demonstrate the concept of Berry phase monopole engineering of the spin Hall effect in non-centrosymmetric silicide TaSi2. We show that while the effective damping-like spin–orbit torque (SOT) efficiency θDLeff of TaSi2 is nearly unchanged from 62 to 288 K (−0.049 to −0.069), θDLeff suddenly increases at high temperatures and becomes nearly double (−0.12) at 346 K. The corresponding intrinsic spin Hall conductivity σDLeff significantly increases at high temperatures, which can be attributed to the increasing contribution from the four degenerate points near the Fermi level via thermal excitation. Our results provide a strategy to enhance θDLeff at high temperatures via Berry phase monopole engineering and pave the way for SOT spintronic devices working at high temperatures.
Predicting freezing points of ternary salt solutions with the multisolute osmotic virial equation
Authors: Binyaminov Hikmat , Sun Henry , Elliott Janet A. W.
Published: December 2023

Previously, the multisolute osmotic virial equation with the combining rules of Elliott et al. has been shown to make accurate predictions for multisolute solutions with only single-solute osmotic virial coefficients as inputs. The original combining rules take the form of an arithmetic average for the second-order mixed coefficients and a geometric average for the third-order mixed coefficients. Recently, we derived generalized combining rules from a first principles solution theory, where all mixed coefficients could be expressed as arithmetic averages of suitable binary coefficients. In this work, we empirically extended the new model to account for electrolyte effects, including solute dissociation, and demonstrated its usefulness for calculating the properties of multielectrolyte solutions. First, the osmotic virial coefficients of 31 common salts in water were tabulated based on the available freezing point depression (FPD) data. This was achieved by polynomial fitting, where the degree of the polynomial was determined using a special criterion that accounts for the confidence intervals of the coefficients. Then, the multisolute model was used to predict the FPD of 11 ternary electrolyte solutions. Furthermore, models with the new combining rules and the original combining rules of Elliott et al. were compared using both mole fraction and molality as concentration units. We find that the mole-fraction-based model with the new combining rules performs the best and that the results agree well with independent experimental measurements with an all-system root-mean-square error of 0.24 osmoles/kg (0.45 °C) and close to zero mean bias for the entire dataset (371 data points).
Leveraging plasmonic hot electrons to quench defect emission in metal–semiconductor nanostructured hybrids
Authors: Sharu Kritika , Chattopadhyay Shashwata , Prajapati K. N. , Mitra J.
Published: December 2023

Modeling light–matter interactions in hybrid plasmonic materials is vital to their widening relevance from optoelectronics to photocatalysis. Here, we explore photoluminescence (PL) from ZnO nanorods (ZNRs) embedded with gold nanoparticles (Au NPs). A progressive increase in Au NP concentration introduces significant structural disorder and defects in ZNRs, which paradoxically quenches defect related visible PL while intensifying the near band edge (NBE) emission. Under UV excitation, the simulated semi-classical model realizes PL from ZnO with sub-bandgap defect states, eliciting visible emissions that are absorbed by Au NPs to generate a non-equilibrium hot carrier distribution. The photo-stimulated hot carriers, transferred to ZnO, substantially modify its steady-state luminescence, reducing NBE emission lifetime and altering the abundance of ionized defect states, finally reducing visible emission. The simulations show that the change in the interfacial band bending at the Au–ZnO interface under optical illumination facilitates charge transfer between the components. This work provides a general foundation to observe and model the hot carrier dynamics and strong light–matter interactions in hybrid plasmonic systems.
Bloch oscillations probed quantum phases in HgTe quantum wells
Authors: Yar Abdullah
Published: December 2023

The semiconductor quantum well based on mercury telluride is characterized by two distinct phases: conventional insulating phase and topological insulating phase with helical edge states. The system undergoes a topological quantum phase transition from one phase to the other, tuned by the critical geometric parameters of the quantum well. It is shown that the quantum states in each phase exhibit distinct flavors of Bloch oscillations, depending strongly on the geometric parameters and crystal momentum of the system. In particular, the group and Berry velocities and the real-space trajectories exhibit pronounced Bloch oscillations. Interestingly, the x- and y-components of the group velocity are interchanged by interchanging their corresponding components of the crystal momentum. In addition, a Gaussian wave packet undergoes distinct time evolution in each quantum phase of the HgTe quantum well. Moreover, the effects of applied in-plane electric and transverse magnetic fields are determined within the framework of Newtonian mechanics, leading to the geometric visualization of such an oscillatory motion. We find that in the presence of both applied in-plane electric and transverse magnetic fields simultaneously, the system undergoes a dynamic phase transition between confined and de-confined states, tuned by the relative strength of the fields. It is argued that the distinct Bloch oscillations originate from the peculiar band structure of HgTe quantum wells in each quantum phase. Furthermore, we find that the direct-current drift velocity in each quantum phase exhibits negative differential conductivity, a hallmark of the Bloch oscillation regime.
Strained AlGaInAs on InP: Bandgap dependence on composition—Model benchmark and optimization
Authors: Zyskowski Marcin , de Louw Nick , Kleijn Steven , Díaz Otero Francisco Javier
Published: December 2023

Influence of chemical composition on the bandgap of AlGaInAs deposited on InP is often calculated using models for unstrained composition and then corrected for strain-induced bandgap energy changes using deformation potentials. This method relies on up to 25 coefficients, many of which are burdened with large uncertainty. In this paper, a large set of experimental data is used to verify the accuracy of existing approaches and to search for optimal deformation potentials. It is shown that the main source of inaccuracy is not the deformation potentials, but the unstrained bandgap formulas. Additionally, a novel model is proposed, yielding the highest accuracy on our dataset. For the first time, composition determination of a quaternary alloy on InP is reported using inductively coupled plasma-optical emission spectrometry, which is used as a benchmark for modeling.
Interface smoothing in short-period W/B4C multilayers using neon ion beam polishing
Authors: IJpes D. , Yakshin A. E. , Sturm J. M. , Ackermann M. D.
Published: December 2023

Short-period 2.5 nm W/B4C multilayers are useful as dispersive Bragg reflectors in wavelength-dispersive x-ray fluorescence. However, high roughness at the W–B4C interfaces deteriorates optical performance. To improve this, low-energy neon ion beam polishing (IBP) has been applied in sputter-deposited 2.5 nm W/B4C multilayers. Two energies, 200 and 50 eV, were investigated to study the effects of polishing by sputter removal (200 eV) and polishing by the mobilization of weakly bound surface atoms (50 eV). Atomic force microscopy and x-ray scattering showed reduced interface roughness for both IBP energies. However, the optical constant profile of 200 eV IBP showed strong W–B4C intermixing and interface asymmetry, leading to significant reflectance loss. In contrast, 50 eV IBP resulted in sharp, symmetric interfaces and increased optical contrast. A 43% peak reflectance at θ = ⁓9.7° grazing for W/B4C with 50 eV IBP was measured at λ = 0.834 nm—a 6.4% increase relative to non-polished W/B4C, corresponding to a 25% increase in integrated reflectance. These results highlight the necessity of using low-energy ion polishing by the mobilization of weakly bound surface atoms in short-period multilayers—rather than polishing by sputter removal.
On the integrated p-type region free of electron blocking layer for AlGaN-based deep-ultraviolet light emitting diodes
Authors: Lang J. , Xu F. J. , Wang J. M. , Zhang L. S. , Ji C. , Guo X. Q. , Ji C. Z. , Zhang Z. Y. , Tan F. Y. , Fang X. Z. , Kang X. N. , Yang X. L. , Tang N. , Wang X. Q. , Ge W. K. , Shen B.
Published: December 2023

AlGaN-based deep-ultraviolet light emitting diodes (DUV-LEDs) with thin p-GaN capping layer have been one of the most promising configurations, thanks to their excellent light extraction potential, which are, however, generally accompanied by insufficient hole supply. In this work, multi-graded p-AlGaN layers are adopted as an integrated p-type region, in which the electron blocking layer (EBL) is taken off to promote the carrier transport. The experimental results show that both the operation voltage and light output power of the DUV-LEDs are improved compared to the traditional ones, leading to a remarkable increase (by 114%) in their wall-plug efficiency. Further analysis confirms that the integrated p-type region serving as the hole supply layer helps holes to avoid the barrier between the p-GaN and integrated p-type region during their transport, and the absence of the EBL further eliminates part of the obstacles for hole drifting, giving rise to an enhanced hole concentration in quantum wells. Meanwhile, thanks to the modulation of the negative polarization induced bulk charges for conduction band, which is introduced within the integrated p-type region, the electron leakage is effectively suppressed even without the EBL, thus improving the device performance dramatically.
A review of the application of spectral methods in computational ocean acoustics
Authors: Wang Yongxian , Tu Houwang , Xu Guojun , Gao Dongbao
Published: December 2023

Spectral methods are a new and niche numerical discretization method with the main characteristic of high accuracy. Spectral methods have been applied in many fields of engineering numerical simulation. Since their introduction into ocean acoustics in 1993, spectral methods have made significant progress in computational ocean acoustics. This article systematically introduces the basic principles of spectral methods, their applicable conditions, and their applications and developments in the normal mode model, the wavenumber integration model, the parabolic equation model, and acoustic Helmholtz equation simulations. At the same time, this article points out the shortcomings of the current application of spectral methods in computational ocean acoustics and potential research directions in the future. The aim is to provide a comprehensive research foundation for subsequent researchers and to promote the application of spectral methods in computational ocean acoustics to go further and deeper.
Experimental study on the dynamics of a spark bubble near the top of a cylinder and associated annular secondary cavitation bubbles
Authors: Xu Yi-Fan , Zhang Shuai , Cui Pu , Wang Shi-Ping , Zhang A-Man
Published: December 2023

This paper presents an experimental study focused on the annular secondary cavitation caused by the interaction between a high-voltage spark bubble and a cylinder. A 2000 V high-voltage underwater electric discharge was used to create the bubble, which reached a maximum diameter of approximately 31 mm. High-speed photography was employed to capture the behavior of the spark bubble and the induced secondary cavitation bubbles. The formation and evolution of the annular secondary cavitation bubbles near the cylinder's edge were captured and analyzed. The study classified the morphology of the annular secondary cavitation bubbles into three different types based on various bubble distances and cylinder diameters. Notably, unique bubble morphologies, such as the terraced bubble shape, were identified, resulting from the coupling between the spark bubble, the annular secondary cavitation bubble, and the cylinder. The interaction between the annular secondary cavitation bubble and the spark bubble, including coalescence, and the resulting effects on bubble shape and period were investigated. The changes of secondary cavitation bubbles are compared when the cylinder has different chamfer angles. Moreover, the study examined the dynamic characteristics of the bubbles, including their shape evolution, jetting behavior, period length, and pressure pulses upon collapse, at various distances from the top-surface of cylinders with different diameters. The experiment also introduced flow visualization with dye into spark bubble experiments for the first time to trace the vortex around the annular secondary bubble. Additionally, the transparency of bubbles in the images was improved through multi-source lighting techniques.
Microswimming under a wedge-shaped confinement
Authors: Sprenger Alexander R. , Menzel Andreas M.
Published: December 2023

Artificial and living microswimmers encounter a large variety of geometric confinements and surfaces in the biological world. Here, we study the low-Reynolds-number dynamics of a microswimmer enclosed by a wedge-shaped free-slip interface. For various opening angles of the wedge, we derive an exact solution for the resulting flow fields using the method of images. In this way, the hydrodynamic interactions between the swimmer and the confining interfaces are examined. In particular, we find attraction or repulsion by the wedge depending on the propulsion mechanism (pusher- or puller-type) and the opening angle of the wedge. Our description should be related to the dynamics of microswimmers in free-standing liquid films of spatially varying thickness.
Flow rate characterization for liquid-immersed granular medium discharging through a hopper
Authors: Fan Jianhua , Zhu Chengzhi , Wang Hongwei , Xu Jintong , Wang Lu
Published: December 2023

The granular sample immersed in a viscous fluid discharge through an orifice connecting a pipe or no pipe has been numerically investigated. A two-dimensional fluid–particle model is adapted, which combines the discrete element method with the lattice Boltzmann method using the partial saturation boundary technique. The discharge rate of liquid-immersed granular media flowing from a hopper is parametrically analyzed by adding a pipe at the outlet, varying fluid properties and orifice sizes. The results show that the existence of the pipe significantly slows down the discharge rate compared with the no-pipe case. A revisited law based on the experimental investigations is proposed by incorporating particle maximum velocity, enabling the prediction of the discharge rate properly. To account for the fluid–particle interaction, the velocity distribution of the particle and its surrounding fluid is analyzed at the local scale. Then, an extension of the kinematic model linking the particle flow rate and velocity distribution is proposed, which allows the prediction of granular discharge from a hopper by considering the influence of the interstitial fluid.
Multiscale modeling of liquid jet breakup in crossflow using an Eulerian/Lagrangian approach
Authors: Zhang Ping , Li Wei , Zhang Teng , Yan Yingwen , Li Jinghua , Tang Hao
Published: December 2023

Liquid atomization is a very complex issue, involving multiple length and time scales over several orders of magnitude. To better understand the atomization characteristics of the main injection in a lean premix prevaporize (LPP) combustor, a volume of fluid (VOF)–particle conversion algorithm Lagrangian particle tracking (LPT) coupled approach was proposed to simultaneously reproduce the primary and secondary breakup processes. A VOF model with an adaptive mesh refinement strategy was used to resolve the liquid disintegration on a large scale. The small liquid structures qualified as droplets were transformed into discrete particles based on particle conversion criteria. Next, these particles were tracked using the LPT method to simulate the secondary breakup process. The proposed coupled method used in the Eulerian/Lagrangian framework was validated against liquid jet in crossflow experimental data. The numerical results achieved good agreement with the experimental data. Finally, the proposed method was used to predict the atomization characteristics of the main injection in an LPP combustor under various aerodynamic conditions. Qualitative and quantitative information about liquid deformation and spray characteristics were obtained, which varied depending on the aerodynamic parameters.
Spall strength of additively repaired 304L stainless steel
Authors: Callanan Jesse G. , Martinez Daniel T. , Ricci Sara , Derby Benjamin K. , Hollis Kendall J. , Fensin Saryu J. , Jones David R.
Published: December 2023

Additive manufacturing has the potential to repair damaged parts, but the performance of additive materials under high strain rate loading is still uncertain—especially with the added complexity of an interface with an existing wrought material. In this work, 304L stainless steel samples were intentionally damaged and then repaired with wire-fed laser additive manufacturing. The samples were subjected to shock loading to generate incipient spall. Velocimetry and post-mortem metallography results show that when the additive repair process parameters are optimized to reduce porosity and match the equation of state of the original material, the influence of the repair region on the shock propagation is negligible. The free-surface velocity profile and internal damage morphology of the repaired sample are shown to be practically identical to the pristine material.
Sensitivity of acoustofluidic particle manipulation to microchannel height in standing surface acoustic wave-based microfluidic devices
Authors: Li Yiming , Liang Dongfang , Kabla Alexandre , Zhang Yuning , Yang Xin
Published: December 2023

In this paper, the flow and particle trajectories, induced by standing surface acoustic waves (SSAWs) in a poly-dimethylsiloxane microchannel, are investigated by establishing a two-dimensional cross-sectional model with the finite element method and improved boundary conditions. Extensive parametric studies are conducted regarding the channel height, ranging from 0.2 to 4.0 times the spacing of the repetitive vertical interference pattern, to investigate its influences on the flow field and microparticle aggregation. The first-order flow field is found to be related to the channel height, exhibiting a periodic spatial distribution and oscillatory variation in its amplitude as the height changes. We theoretically analyze the propagation mechanism of the acoustic waves in the vertical direction and thus determine the periodicity of the wave interference pattern. Furthermore, we find that the speed of the particle aggregation is a function of the channel height, so the channel height can be optimized to maximize the strength of the first-order flow field and thus minimize the time of particle aggregation. The optimum heights can reduce the aggregation time by up to 76%. In addition, the acoustophoretic motions of microparticles exhibit a spatially dependent pattern when the channel height becomes larger than a quarter of the wavelength of the SAW, which can be explained by the change in the ratio between the radiation force and the streaming drag force from position to position. Our findings provide guidelines to the design and optimization of SSAW-based acoustofluidic devices.
Competition between built-in polarization and p–n junction field in III-nitride heterostructures
Authors: Turski Henryk , Chlipala Mikolaj , Zdanowicz Ewelina , Rogowicz Ernest , Muziol Grzegorz , Moneta Joanna , Grzanka Szymon , Kryśko Marcin , Syperek Marcin , Kudrawiec Robert , Skierbiszewski Czeslaw
Published: December 2023

The high built-in polarization field is a fingerprint of III-nitride heterostructures. Alloy composition and doping profile significantly affect the magnitude of the electric field present in subsequent layers, but the sign of the electric field is usually defined by substrate polarity and external bias. Here, we propose to utilize acceptor and donor doping concentrations exceeding 1020 cm−3 to obtain a high junction field that can solely abolish built-in polarization for a polar (0001) InGaN/GaN quantum well (QW). We have used photoluminescence (PL), time-resolved PL (TRPL), and contactless electroreflectance in order to gain insight into the strength of the electric field present in the grown heterostructures. Good match between expected and measured electric field values was obtained. A dramatic decrease in the luminescence lifetime for a flat QW was confirmed using TRPL. The presented results open a way to realize devices that profit from the low built-in field, like photodetectors, using abundant polar substrates.
Topological Mott transistor with high current density based on hydrogen-terminated diamond
Authors: Kim Hyun-Tak , Qazilbash M. M.
Published: December 2023

The mechanism for the high drain-source current density, IDS≈ 1.3 A/mm, measured in a field effect transistor based on hydrogen-terminated diamond, is explained by the Mott insulator-metal transition (IMT). A local metal phase satisfying the Mott criterion for an IMT occurs in a p-type semiconductor formed by coupling between hydrogen and carbon on the surface of diamond. The local Mott metal phase on the surface of a p-type semiconductor leads to high carrier and current densities, and the transistor utilizing this effect is construed as a Mott power transistor. A channel material consisting of local Mott metal regions on the surface of a p-type semiconductor, such as hydrogen-terminated diamond, may be considered an inhomogeneous, topological Mott insulator.
Defects of perovskite semiconductor CsPbBr3 investigated via photoluminescence and thermally stimulated current spectroscopies
Authors: Liu Zhifu , Peters John A. , Bayikadi Khasim Saheb , Klepov Vladislav , Pan Lei , Pandey Indra Raj , Kanatzidis Mercouri G. , Wessels Bruce W.
Published: December 2023

Halide perovskites are essential materials for hard radiation detectors at ambient temperature. To improve detector performance, charge transport must be investigated and optimized. Using photoluminescence (PL) and thermally stimulated current (TSC) spectroscopies, we investigate photogenerated charge carriers in Bridgman-grown CsPbBr3 single crystals to understand the nature of charge transport. PL spectroscopy of these halide perovskites revealed the presence of strong emission bands at the band edge, which were attributed to free or bound excitons. It is shown that a wide broadening of the excitonic linewidth in these halide perovskites arises from strong exciton–phonon coupling, which is substantially dominated by longitudinal optical phonons via Fröhlich interaction. An additional contribution due to the presence of ionized impurities was also observed. Crystals with a detectable sensitivity to high-energy gamma radiation are characterized by a higher intensity and a narrower linewidth of the principal PL peak at 2.326 eV. Defect states beyond 2.214 eV have a negative impact on detector sensitivity to high-energy gamma radiation. TSC spectroscopy reveals an array of trap levels spanning 0.15–0.70 eV, attributed to intrinsic point defects and multiple extrinsic defects involving dopants or impurities. Defects identified included Cs and Br vacancies, as well as Pb interstitials with concentrations in the 1011–1016 cm−3 range. Understanding how the synthesis process impacts the types and concentrations of the defects present is currently under investigation. Elimination or suppression of the defect/trap states should result in halide perovskite materials with longer carrier diffusion lengths and improved detector characteristics.
The limit of anisotropic epitaxial lateral overgrowth in heteroepitaxial systems
Authors: Zhang Yiwen , Ma Danhao , Lin Yiding , Michel Jurgen , Wen Rui-Tao
Published: December 2023

The separation of Ge and Si by an electrically isolating dielectric layer is essential to yield high efficiency for optical telecommunication applications and electronic applications such as Ge MOSFETs. Ge epitaxial lateral overgrowth (ELOG) is a promising approach to achieve Ge on Si separated by a thin dielectric layer. However, a general understanding of the anisotropic dynamics of ELOG Ge on Si is limited, which prevents its wide adoption. In this paper, we report how the orientation and width of the dielectric layer controls the ELOG. A competitive ELOG from perpendicular directions on a dielectric strip leads to a rapid growth along the long axis of the dielectric layer, or a mixed coalescence from perpendicular directions yielding various Ge confined configurations at the Ge/dielectric-layer interface. Especially, an angle of 7.5° between dielectric-layer and Si [110] axis shows the most pronounced unidirectional ELOG. ELOG disappears as the width of the dielectric mask exceeds 5.0 μm. The results reported here provide a general framework for ELOG of semiconductor materials.
Doubling down on density-functional theory
Authors: Becke Axel D.
Published: December 2023

In a recent paper, Becke et al. [J. Chem. Phys. 158, 151103 (2023)] presented a novel double hybrid density functional, “DH23,” whose terms are based on good physics. Its 12 coefficients were trained on the GMTKN55 (general main-group thermochemistry, kinetics, and noncovalent interactions) chemical database of Goerigk et al. [Phys. Chem. Chem. Phys. 19, 32184 (2017)]. The lowest GMTKN55 “WTMAD2” error to date for any hybrid or double hybrid density functional was obtained (1.76 kcal/mol). Here, we make some revisions to DH23 and test its efficacy on reference data beyond GMTKN55, namely, organometallic reaction energies and barrier heights. The results confirm that DH23 is robust outside its training set. In the process, a slightly smaller GMTKN55 WTMAD2 of 1.73 kcal/mol is achieved.
A reconfigurable acoustic coding metasurface for tunable and broadband sound focusing
Authors: Song Ailing , Bai Yazhu , Sun Chaoyu , Xiang Yanxun , Xuan Fu-Zhen
Published: December 2023

The targeted concentration of acoustic waves has significant implications for industrial nondestructive testing, ultrasound diagnosis, and medical treatment. Most conventional sound-focusing metasurfaces suffer from an untunable focus, narrow bandwidth, and fixed geometric configurations, which severely constrain their practical utility. In this paper, we propose a reconfigurable acoustic coding metasurface composed of two coding units with high transmittance and transmitted phases of 0 and π for realizing tunable and broadband sound focusing. Through the straightforward manipulation of each unit structure and alterations in the coding sequences, precise control of the focus position across the entire working plane is attainable, enabling both tunable axial-axis and off-axis sound-focusing effects. Moreover, the sound-focusing performance of the proposed metasurface is excellent within a broad frequency range from 3000 to 5500 Hz. The experimental results are consistent with theoretical expectations and numerical simulations. This work lays a practical foundation for the design of acoustic devices for tunable and broadband sound focusing.
Asymmetric fracture behavior in ferroelectric materials induced by flexoelectric effect
Authors: Guo Yangqin , Liu Chang , Li Xiangyu
Published: December 2023

Ferroelectric materials are widely used in actuators, exciters, and memory devices due to their excellent electromechanical properties. However, the instinctive brittleness of ferroelectric materials makes them easy to fracture under external load. Since giant strain gradient can be easily generated near the crack tip, the flexoelectric effect is indispensable in the research of fracture properties of ferroelectric materials. With the combination of time-dependent Ginzburg–Landau theory and phase-field model, the electromechanical behavior of PbTiO3 in the vicinity of the crack tip is determined in this work. The simulation results demonstrate that the domain structure near the crack tip becomes asymmetric with the flexoelectric effect. The polarization switching-induced toughening, which is characterized by the J-integral, depends on the direction of the crack relative to the original polarization orientation. Furthermore, the longitude flexoelectric coefficient f11 has more significant impact on the fracture toughness than that of the transverse flexoelectric coefficient f12 and the shear flexoelectric coefficient f44. The results of the present work suggest that the flexoelectric effect must be considered in the reliable design of ferroelectric devices.
Capacitance–voltage extraction method for the deep-level defect distribution in organic photodiode
Authors: Zuo Wencai , Liu Sai , Li Haoyang , Zhang Lianjie , Wu Weijing , Chen Junwu , Peng Junbiao
Published: December 2023

This paper proposes a method to extract deep-level trap states of the organic photodiode by capacitance–voltage (CV) measurement. The relationship between the trapped charge density and the surface potential can be determined by solving Poisson's equation, while employing Gauss's theorem to establish a correlation between the charge density and the CV characteristics. Consequently, deep-level trap states can be analytically obtained by the conventional CV measurement. Experimental results on P3HT:PCBM devices demonstrate that the deep trap distribution obtained by this method can be well connected with the capacitance–frequency method. Furthermore, our CV method yields a total trap concentration, which closely aligns with that obtained through Mott–Schottky relation. In conclusion, this method provides an effective approach for quantifying deep trap state density of organic photodiode.
On nonmodal stability of elliptic pipe flow
Authors: Demyanko Kirill V. , Klyushnev Nikita V.
Published: December 2023

The temporal nonmodal stability of the Poiseuille flow in a pipe of axially uniform elliptic cross section is numerically studied. In particular, it is shown that the maximum amplification of kinetic energy of disturbances depends significantly on the pipe aspect ratio, and this dependence is non-monotonic. It agrees with the corresponding dependence of the energy critical Reynolds number, which is the lower limit of the Reynolds numbers enabling the growth of disturbance kinetic energy. In other words, changing the aspect ratio similarly affects both nonmodal and monotonic stability of the flow. The optimal disturbances displaying the maximum amplification are streamwise counter-rotating vortices. These disturbances are streamwise uniform at sufficiently large Reynolds numbers and may become streamwise harmonic as the Reynolds number decreases. In addition, their symmetry with respect to the cross section axes varies with the aspect ratio. Thus, the obtained results suggest that changing the aspect ratio may be a perspective tool for the passive control of the subcritical laminar-turbulent transition in pipe flows. In other words, this factor is worth considering when designing various devices (e.g., heat exchangers or ventilation systems) containing pipes to enhance their efficiency.
Plasmon-induced magnetic anapole mode assisted strong field enhancement
Authors: Wang Jingyu , Yang Weimin , He Yonglin
Published: December 2023

Optical metamaterials, sensing, nonlinear optics, and surface-enhanced spectroscopies have witnessed the remarkable potential of the anapole mode. While dielectric particles with a high refractive index have garnered significant attention in recent years, the exploration of plasmonic anapole modes with intense localized electric field enhancements in the visible frequency range remains limited. In this study, we present a theoretical investigation on the relationship between the strongest near-field response and magnetic anapole modes, along with their substantial enhancement of Raman signals from probing molecules. These captivating findings arise from the design of a practical metallic oblate spheroid–film plasmonic system that generates magnetic anapole resonances at frequencies within the visible–near-infrared range. This research not only sheds light on the underlying mechanisms in a wide range of plasmon-enhanced spectroscopies but also paves the way for innovative nano-device designs.
Application of the unified equation of bubble dynamics for simulating the large-scale air-gun bubble with migration effect
Authors: Liu Yi , Zhang Shuai , Li Shuai , Zhang A-Man
Published: December 2023

How to effectively reduce the high-frequency output caused by excessively steep initial peak slope and enhance the low-frequency output generated by bubble oscillation has become present research interest in seismic source design. The most effective way to improve the low-frequency content of a seismic source is to increase its chamber volume. However, the size of air-gun bubbles generated by large-volume air-gun sources has increased by several hundred times compared to traditional high-pressure air guns, which has made the migration phenomenon of bubbles no longer negligible. The previous air-gun bubble dynamics models did not comprehensively account for the effects caused by bubble migration phenomenon. In this paper, we have developed an air-gun bubble dynamics model based on unified equation for bubble dynamics, and the newly established model demonstrates a closer alignment with experimental data compared to models based on the Gilmore and Keller equations. Based on this, the influence of the design parameters of air-gun seismic source on the bubble migration is studied. It explores the ramifications of migration on the dynamic properties of air-gun bubbles and the signatures of seismic sources. Additionally, we examine how incoming flow velocity magnitude and air-gun design parameters influence the signatures of air-gun seismic sources. Finally, we investigate the impact of both the spacing between dual guns and the horizontal movement of bubbles caused by mutual attraction on the signatures of dual-gun sources.
Kohn–Sham accuracy from orbital-free density functional theory via Δ-machine learning
Authors: Kumar Shashikant , Jing Xin , Pask John E. , Medford Andrew J. , Suryanarayana Phanish
Published: December 2023

We present a Δ-machine learning model for obtaining Kohn–Sham accuracy from orbital-free density functional theory (DFT) calculations. In particular, we employ a machine-learned force field (MLFF) scheme based on the kernel method to capture the difference between Kohn–Sham and orbital-free DFT energies/forces. We implement this model in the context of on-the-fly molecular dynamics simulations and study its accuracy, performance, and sensitivity to parameters for representative systems. We find that the formalism not only improves the accuracy of Thomas–Fermi–von Weizsäcker orbital-free energies and forces by more than two orders of magnitude but is also more accurate than MLFFs based solely on Kohn–Sham DFT while being more efficient and less sensitive to model parameters. We apply the framework to study the structure of molten Al0.88Si0.12, the results suggesting no aggregation of Si atoms, in agreement with a previous Kohn–Sham study performed at an order of magnitude smaller length and time scales.
Magneto-electric coupling beyond van der Waals interaction in two-dimensional multiferroic heterostructures
Authors: Jin Chao , Liu Chang , Ren Fengzhu , Wang Bing , Jia Minglei , Gu Qinfen
Published: December 2023

Exploring two-dimensional (2D) multiferroic systems with strong magneto-electric coupling properties holds significant application value in nanoscale spintronics devices. However, due to the weak interlayer van der Waals interactions, strong magneto-electric coupling in 2D heterostructures is relatively rare. By using first-principles simulations, we demonstrate that in the NiPS3/Sc2CO2 heterostructure, the ferroelectric polarization switching of the Sc2CO2 layer induces a transition in the magnetic ground state of the NiPS3 layer from the ferromagnetic state to antiferromagnetic ordering, accompanied by a transformation from a semiconductor to a half-metallic state. This magnetic phase transition is caused by a novel magneto-electric coupling mechanism: the polarization switching changes the band alignment between the two materials and then induces a significant interlayer charge transfer, leading to the emergence of Stoner itinerant ferromagnetism. In addition, the polarization switching can also change the magnetic anisotropy from an easy magnetization plane to an easy magnetization axis. These results not only offer a promising multiferroic heterostructure for nonvolatile memory devices and magnetic sensors but also provide a feasible approach for designing multiferroic system with strong magneto-electric coupling.
Two-dimensional
α
-In2Se3 memory devices from resistive switching to synaptic plasticity
Authors: Ma Ting , Han Shuangshuang , Yang Di , Ye Yun , Liu Ying , Shen Zhitao , Li Fumin , Li Huilin , Chen Chong
Published: December 2023

We employ two-dimensional (2D) α-In2Se3 nanosheets and polymethyl methacrylate (PMMA) materials to develop three types of devices with different resistive switching (RS) layer structures and deeply study the electrical properties and physical mechanisms of these devices. It is confirmed that the pure 2D α-In2Se3 nanosheet-based RS device is a mode of ferroelectric regulation of the potential barrier, exhibiting memristor characteristics that can mimic the synaptic plasticity. Meanwhile, PMMA can improve the RS properties of the α-In2Se3 nanosheet-based device, including the appropriate switching ratio, narrow ratio distribution, and good endurance and retention capability, but the device's physical mechanism changes to charge trapping assisted hopping mechanism from the ferroelectric regulation of the potential barrier.
Sliding motion of highly deformed droplets on smooth and rough surfaces: Shape oscillation, chaotic breakage, corner shape, and pearling
Authors: Tsao Yu-Hao , Liao Ying-Chih , Tsao Heng-Kwong
Published: December 2023

The sliding behavior of droplets on smooth and rough surfaces with various surface wettabilities is investigated by many-body dissipative particle dynamics simulations. On a smooth surface, as the driving force (Bo) increases, the droplet shape and velocity (Cac) before breakage can be classified into four distinct regimes: (I) nearly spherical cap with Cac∝Bo; (II) oval shape with negative deviation from the linear relation; (III) elongated shape without a neck, where Cac decreases with increasing Bo; and (IV) oscillation of an elongated shape with fluctuating sliding velocity. On rough surfaces, corner-shaped droplets, which are absent on a smooth surface, can be observed. A further increase in Bo leads to the formation of cusp and pearling. Different from pinching-off on rough surfaces, which produces a cascade of smaller droplets through groove-induced shedding, chaotic breakage of a droplet on a smooth surface is caused by an unsteady flow field. Finally, a universal linear relationship between the sliding velocity based on the surface velocity (Cas) and the modified driving force (Bo**) is derived to take into account the effects of surface wettability and roughness.
Perpendicular magnetic anisotropy in Bi-substituted yttrium iron garnet films
Authors: Das Sreeveni , Mansell Rhodri , Flajšman Lukáš , Yao Lide , van Dijken Sebastiaan
Published: December 2023

Magnetic garnet thin films exhibiting perpendicular magnetic anisotropy (PMA) and ultra-low damping have recently been explored for applications in magnonics and spintronics. Here, we present a systematic study of PMA and magnetic damping in bismuth-substituted yttrium iron garnet (Bi-YIG) films grown on sGGG (111) substrates by pulsed laser deposition. Films with thicknesses ranging from 5 to 160 nm are investigated. Structural characterization using x-ray diffraction and reciprocal space mapping demonstrates the pseudomorphic growth of the films. The films exhibit perpendicular magnetic anisotropy up to 160 nm thickness, with the zero-magnetic field state changing from fully saturated for low thicknesses to a dense magnetic stripe pattern for thicker films. The films show a ferromagnetic resonance (FMR) linewidth of 100–200 MHz with a Gilbert damping constant of the order of 4×10−3. The broad FMR linewidth is caused by inhomogeneities of magnetic properties on micrometer length scales.
Robust diamond-embedded microwave antenna for optimizing quantum sensing using nitrogen-vacancy center ensembles
Authors: Guo Yuhang , Zhao Jiaxin , Weng Changfeng , Lin Shengran , Yang Yuanjie , Zhu Wei , Lou Liren , Wang Guanzhong
Published: December 2023

The nitrogen-vacancy (NV) color center in diamond has emerged as a promising candidate for quantum sensing. In this study, we propose a diamond-embedded metal antenna for magnetic detection utilizing NV center ensembles. Our approach involved employing nanofabrication and microwave plasma chemical vapor deposition techniques to fabricate the metal antenna and diamond epilayer. By directly embedding the antenna into the diamond, we effectively minimize external environmental interference, leading to improved device stability and reusability. Moreover, this integration enhances the device's compactness, making it highly suitable for on-chip quantum sensing applications. The innovative antenna design holds great potential for the development of future integrated quantum sensing devices based on NV centers in diamond.