bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functional group induced transformations in stacking and electron structure in Mo2CT
x
/NiS heterostructures
Authors: Liu Jiamin , Li Guo , Zhang Xinxu , Wei Jiahao , Jia Hui , Wu Yulong , Liu Changlong , Li Yonghui 
Published: June 2024

Abstract
The two-dimensional transition metal carbide/nitride family (MXenes) has garnered significant attention due to their highly customizable surface functional groups. Leveraging modern material science techniques, the customizability of MXenes can be enhanced further through the construction of associated heterostructures. As indicated by recent research, the Mo2CT
x
/NiS heterostructure has emerged as a promising candidate exhibiting superior physical and chemical application potential. The geometrical structure of Mo2CT
x
/NiS heterostructure is modeled and six possible configurations are validated by Density Functional Theory simulations. The variation in functional groups leads to structural changes in Mo2CT
x
/NiS interfaces, primarily attributed to the competition between van der Waals and covalent interactions. The presence of different functional groups results in significant band fluctuations near the Fermi level for Ni and Mo atoms, influencing the role of atoms and electron’s ability to escape near the interface. This, in turn, modulates the strength of covalent interactions at the MXenes/NiS interface and alters the ease of dissociation of the MXenes/NiS complex. Notably, the Mo2CO2/NiS(P63/mmc) heterostructure exhibits polymorphism, signifying that two atomic arrangements can stabilize the structure. The transition process between these polymorphs is also simulated, further indicating the modulation of the electronic level of properties by a sliding operation.
Structural phase transition and potential superconductivity initiated by pressure-driven in 1T–CrSe2
Authors: Wu Ming , Lv Xindeng , Zhao Wendi , Liu Sirui , Dan Yaqian , Fang Yuqiang , Huang Yanping , Cui Tian 
Published: June 2024

Abstract
The exploration of the superconducting properties of antiferromagnetic parent compounds containing transition metals under pressure provides a unique idea for finding and designing superconducting materials with better performance. In this paper, the close relationship between the possible superconductivity and structure phase transition of the typical van der Waals layered material 1 T–CrSe2 induced by pressure is studied by means of electrical transport and x-ray diffraction for the first time. We introduce the possibility of pressure-induced superconductivity at 20 GPa, with a critical T
c of approximately at 4 K. The superconductivity persists up to the highest measured pressure of 70 GPa, with a maximum T
c ∼ 5 K at 24 GPa. We observed a structure phase transition from P-3 m1 to C2/m space group in the range of 9.4–11.7 GPa. The results show that the structural phase transition leads to the metallization of 1 T–CrSe2 and the further pressure effect makes the superconductivity appear in the new structure. The material undergoes a transition from a two-dimensional layered structure to a three-dimensional structure under pressure. This is the first time that possible superconductivity has been observed in 1 T–CrSe2.
Zero-field magnetic skyrmions in exchange-biased ferromagnetic–antiferromagnetic bilayers
Authors: Pankratova M , Eriksson O , Bergman A 
Published: June 2024

Abstract
We report on the stabilization of ferromagnetic skyrmions in zero external magnetic fields, in exchange-biased systems composed of ferromagnetic–antiferromagnetic (FM-AFM) bilayers. By performing atomistic spin dynamics simulations, we study cases of compensated, uncompensated, and partly uncompensated FM-AFM interfaces, and investigate the impact of important parameters such as temperature, inter-plane exchange interaction, Dzyaloshinskii–Moriya interaction, and magnetic anisotropy on the skyrmions appearance and stability. The model with an uncompensated FM-AFM interface leads to the stabilization of individual skyrmions and skyrmion lattices in the FM layer, caused by the effective field from the AFM instead of an external magnetic field. Similarly, in the case of a fully compensated FM-AFM interface, we show that FM skyrmions can be stabilized. We also demonstrate that accounting for interface roughness leads to stabilization of skyrmions both in compensated and uncompensated interface. Moreover, in bilayers with a rough interface, skyrmions in the FM layer are observed for a wide range of exchange interaction values through the FM-AFM interface, and the chirality of the skyrmions depends critically on the exchange interaction.
Design of higher Chern number two-band structures from topological defect perspective
Authors: Chang Zhi-Wen , Hao Wei-Chang , Liu Xin 
Published: June 2024

Abstract
In this article, we propose two methods for designing higher Chern number models from the topological defect perspective. Based on the fact that the Chern number is equal to a summation of the charges of meron defects, we show that the higher Chern number structures can be realized by either moving the positions of merons or increasing the amount of them. The combination of the two methods is also verified to be a viable approach. We shall construct several models and investigate their energy spectrum. More than one gapless state can be observed on the edges of these models. Expectedly, our theory promises to provide not only a simple approach to obtain the Chern number without computing any integrals, but also a practical technique for new material design.
Intra-strand phosphate-mediated pathways in microsolvated double-stranded DNA
Authors: Polycarpou Georgia , Skourtis Spiros S 
Published: June 2024

Abstract
We argue that dry DNA charge transport in molecular junctions, over distances of tens of nanometers, can take place via independent intra-strand pathways involving the phosphate groups. Such pathways explain recent single-molecule experiments that compare currents in intact and nicked 100 base-pair double-stranded DNA. We explore the conditions that favor independent intra-strand transport channels with the participation of the phosphate groups, as opposed to purely base-mediated transport involving the pi-stacked bases and inter-strand transitions. Our computations demonstrate how long-distance transport pathways in DNA are tuned by the degree of solvation, which affects the level of dynamic disorder in the pi-stacking, and the energies of phosphate-group molecular orbitals.
Room temperature thermal rectification in suspended asymmetric graphene ribbon
Authors: Islam Mohammad Razzakul , Yongzheng Liu , Kareekunnan Afsal , Mizuta Hiroshi 
Published: June 2024

Abstract
Thermal rectifiers are essential in optimizing heat dissipation in solid-state devices to enhance energy efficiency, reliability, and overall performance. In this study, we experimentally investigate the thermal rectification phenomenon in suspended asymmetric graphene ribbons (GRs). The asymmetry within the graphene is introduced by incorporating periodic parallel nanoribbons on one side of the GR while maintaining the other side in a pristine form. Our findings reveal a substantial thermal rectification effect in these asymmetric graphene devices, reaching up to 45% at room temperature and increasing further at lower environmental temperatures. This effect is attributed to a significant thermal conductivity contrast between pristine graphene and nanoribbon graphene within the asymmetric structure. We observe that the incorporation of nanoribbons leads to a notable reduction in thermal conductivity, primarily due to phonon scattering and bottleneck effects near the nanoribbon edges. These findings suggest that graphene structures exhibiting asymmetry, facilitated by parallel nanoribbons, hold promise for effective heat management at the nanoscale level and the development of practical phononic devices.
Silicon nanowire piezoresistor and its applications: a review
Authors: Raman Srinivasan , K V Meena , S Vetrivel , Sankar A Ravi 
Published: June 2024

Abstract
Monocrystalline bulk silicon with doped impurities has been the widely preferred piezoresistive material for the last few decades to realize micro-electromechanical system (MEMS) sensors. However, there has been a growing interest among researchers in the recent past to explore other piezoresistive materials with varied advantages in order to realize ultra-miniature high-sensitivity sensors for area-constrained applications. Of the various alternative piezoresistive materials, silicon nanowires (SiNWs) are an attractive choice due to their benefits of nanometre range dimensions, giant piezoresistive coefficients, and compatibility with the integrated circuit fabrication processes. This review article elucidates the fundamentals of piezoresistance and its existence in various materials, including silicon. It comprehends the piezoresistance effect in SiNWs based on two different biasing techniques, viz., (i) ungated and (ii) gated SiNWs. In addition, it presents the application of piezoresistive SiNWs in MEMS-based pressure sensors, acceleration sensors, flow sensors, resonators, and strain gauges.
Existence and multiplicity of peaked bound states for nonlinear Schrödinger equations on metric graphs
Authors: Chen Haixia , Dovetta Simone , Pistoia Angela , Serra Enrico 
Published: June 2024

Abstract
We establish existence and multiplicity of one-peaked and multi-peaked positive bound states for nonlinear Schrödinger equations on general compact and noncompact metric graphs. Precisely, we construct solutions concentrating at every vertex of odd degree greater than or equal to 3. We show that these solutions are not minimizers of the associated action and energy functionals. To the best of our knowledge, this is the first work exhibiting solutions concentrating at vertices with degree different than 1. The proof is based on a suitable Ljapunov–Schmidt reduction.
Using storytelling to foster the teaching and learning of gravitational waves physics at high-school
Authors: Tuveri M , Steri A , Fadda D 
Published: June 2024

Abstract
Studies in Physics Education Research show that interdisciplinary approaches in education foster students’ motivation, creativity, curiosity, and interest in physics. We discuss their features and potential role in bringing contemporary physics topics to high school and how to use them to integrate formal educational programs. We make an explicit example of the use of storytelling and theatrical techniques to introduce secondary school students to black holes and gravitational wave topics. The Educational Division of the Physics Department at the University of Cagliari designed the activity. Participants were 200 high-school students (17 to 19 years old) from five schools (scientific, humanities) in Sardinia. Through a research questionnaire, we measure the efficacy of using artistic tools to communicate and teach the proposed subjects. We collected 76 answers. Results show that our methodology helps introduce students to contemporary physics themes, fostering their interest and learning of such content. Students from the humanities significantly appreciated the use of poetry and artistic tools more than their scientific peers. Finally, we discuss the potentiality of our approach in orientating students towards a STEAM (STEM and Arts) career.
Machine learning-based atrial fibrillation detection and onset prediction using QT-dynamicity
Authors: Grégoire Jean-Marie , Gilon Cédric , Vaneberg Nathan , Bersini1 Hugues , Carlier Stéphane 
Published: June 2024

Abstract

Objective. This study examines the value of ventricular repolarization using QT dynamicity for two different types of atrial fibrillation (AF) prediction. Approach. We studied the importance of QT-dynamicity (1) in the detection and (2) the onset prediction (i.e. forecasting) of paroxysmal AF episodes using gradient-boosted decision trees (GBDT), an interpretable machine learning technique. We labeled 176 paroxysmal AF onsets from 88 patients in our unselected Holter recordings database containing paroxysmal AF episodes. Raw ECG signals were delineated using a wavelet-based signal processing technique. A total of 44 ECG features related to interval and wave durations and amplitude were selected and the GBDT model was trained with a Bayesian hyperparameters selection for various windows. The dataset was split into two parts at the patient level, meaning that the recordings from each patient were only present in either the train or test set, but not both. We used 80% on the database for the training and the remaining 20% for the test of the trained model. The model was evaluated using 5-fold cross-validation. Main results. The mean age of the patients was 75.9 ± 11.9 (range 50–99), the number of episodes per patient was 2.3 ± 2.2 (range 1–11), and CHA2DS2-VASc score was 2.9 ± 1.7 (range 1–9). For the detection of AF, we obtained an area under the receiver operating curve (AUROC) of 0.99 (CI 95% 0.98–0.99) and an accuracy of 95% using a 30 s window. Features related to RR intervals were the most influential, followed by those on QT intervals. For the AF onset forecast, we obtained an AUROC of 0.739 (0.712–0.766) and an accuracy of 74% using a 120s window. R wave amplitude and QT dynamicity as assessed by Spearman’s correlation of the QT-RR slope were the best predictors. Significance. The QT dynamicity can be used to accurately predict the onset of AF episodes. Ventricular repolarization, as assessed by QT dynamicity, adds information that allows for better short time prediction of AF onset, compared to relying only on RR intervals and heart rate variability. Communication between the ventricles and atria is mediated by the autonomic nervous system (ANS). The variations in intraventricular conduction and ventricular repolarization changes resulting from the influence of the ANS play a role in the initiation of AF.
Tokamak to stellarator conversion using permanent magnets
Authors: Madeira M , Jorge R 
Published: June 2024

Abstract
With the advances in the optimization of magnetic field equilibria, stellarators have become a serious alternative to the tokamak, bringing this concept to the forefront of the pursuit of fusion energy. In order to be successful in experimentally demonstrating the viability of optimized stellarators, we must overcome any potential hurdles in the construction of its electromagnetic coils. Finding cost-effective ways of increasing the number of operating optimized stellarators could be key in cementing this magnetic confinement concept as a contender for a reactor. In this work, an alternative to modular coils, permanent magnets, are studied and are shown to enable the possibility of converting a tokamak into a stellarator. This is then applied to the case of ISTTOK tokamak, where an engineering design study is conducted.
Spectral simulation of multivalent collisional-radiative model for W25+–W28+ from EBIT to tokamak plasmas
Authors: Li B L , Qu F H , Xie Y M , Liu X , Zhang X W , Yao K , Yang Y , Wei B , Zou Y , Xiao J 
Published: June 2024

Abstract
Accurate and reliable atomic modeling of tungsten ions holds significance for both spectral data analysis and the investigation of tungsten behavior within fusion plasma. To examine the impact of various atomic processes on spectral lines, a collisional-radiative model (CRM) involving multiple charge states for tungsten ions was performed with level-to-level processes with configuration interaction, including spontaneous emission, electron collisional ionization, collisional (de)excitation, radiative recombination, charge exchange, resonant capture, and autoionization. The evolution of M1 spectral lines of W25+–W28+ in the 330–540 nm range was measured using the SH-HtscEBIT and was successfully replicated by the multivalent CRM. The photon emission coefficients (PECs) associated with these M1 transitions in fusion plasma have also been furnished, revealing their minimal sensitivity to the influence of recombination and ionization processes. The verification of these PECs’ properties holds potential for the forthcoming density diagnosis of tungsten ions in Tokamak. Subsequently, the multivalent CRM was also conducted to explore the impact of dielectronic recombination on extreme ultraviolet spectra. While resonant capture does lead to an augmentation in the population of autoionizing levels, the contribution of dielectronic recombination to spectral lines for W26+ and W27+ within the 2–8 nm range remains relatively insignificant.
Effect of stress control by growth adjustment on the edge thread dislocation density of AlN grown on the sapphire
Authors: Zhang Yuheng , Yang Jing , Liang Feng , Liu Zongshun , Hou Yufei , Liu Bing , Zheng Fu , Liu Xuefeng , Zhao Degang 
Published: June 2024

Abstract
The relationship between stress and dislocation density in MOCVD epitaxial AlN was studied. It has been found that the aluminum nitride (AlN) epitaxial layer generates tensile stress when the crystal islands are merged. By controlling the size and density of crystal islands at the end of 3D growth, the tensile stress generated during epitaxy can be effectively reduced. Mechanical calculations show that there is a linear relationship between the edge thread dislocations density of AlN and the tensile stress during growth. By controlling the stress during AlN growth below 0.1 Gpa, a high-quality AlN sample with an edge thread dislocation density of 6.31 × 107 cm−2 was obtained.
Anomalous Hall effect sensitive to magnetic monopoles and skyrmion helicity in spin–orbit coupled systems
Authors: Mochida Jun , Ishizuka Hiroaki 
Published: June 2024

Abstract
Magnetic textures, such as skyrmions and domain walls, engender rich transport phenomena, including anomalous Hall effect and nonlinear response. In this work, we discuss an anomalous Hall effect proportional to the net magnetic monopole charge and dependent on the skyrmion helicity that occurs by a skew scattering in a noncentrosymmetric two-dimensional magnet. This mechanism, which arises from the spin–orbit interaction (SOI), gives rise to a finite anomalous Hall effect in a ferromagnetic domain wall whose spins rotate in the xy plane despite no out-of-plane magnetic moment. We show that the presence and absence of the monopole contribution is related to crystal symmetry, which gives a guideline for finding candidate materials beyond the Rashba model. The results demonstrate the rich features arising from the interplay of SOI and magnetic textures, and their potential for detecting various magnetic textures in micrometer devices.
Polarization-multiplexing graphene-based coding metasurface for flexible terahertz wavefront control
Authors: Lu Jinliang , He Xunjun , Jiang Jiuxing , Yao Yongtao , Zhang Ying 
Published: June 2024

Abstract
In terahertz wireless communication systems, flexible wavefront control devices based on various structure metasurfaces have attracted enormous attention for next-generation communication. In general, tunable terahertz metasurfaces integrated with active materials or MEMS technologies are used for dynamic wavefront control. However, most existing metasurfaces suffer from various limitations, including intrinsic properties of active materials, low reliability of MEMS technologies, and single polarization mode of incident waves, which hinders their development and application. To address these challenges, herein, we design two types of reflective graphene-based coding metasurfaces for active wavefront control. The metasurface coding meta-atom is composed of a graphene split-ring resonator, a dielectric layer, and a metal ground plane. By simply rotating the coding meta-atom, independent 2π phase coverage for circularly polarized (CP) or linearly polarized (LP) illumination can be achieved, enabling polarization multiplexing. Thus, a metasurface (MS-1) is constructed based on the vortex phase profile to generate different wavefronts. Moreover, these wavefronts can be actively switched between a vortex beam, a multi-beam, and a specular reflection beam by altering the polarization mode of the incident waves and the Fermi level of the graphene coding regions Additionally, another metasurface (MS-2) is developed according to the parabolic phase profile to create a tunable metalens that allows active control over focal intensity and depth by adjusting the Fermi level of graphene. Such wavefront-controlled metasurfaces have high capacity and integration, making them very promising for potential applications in terahertz communication and imaging systems.
A novel discretized physics-informed neural network model applied to the Navier–Stokes equations
Authors: Khademi Amirhossein , Dufour Steven 
Published: June 2024

Abstract
The advancement of scientific machine learning (ML) techniques has led to the development of methods for approximating solutions to nonlinear partial differential equations (PDE) with increased efficiency and accuracy. Automatic differentiation has played a pivotal role in this progress, enabling the creation of physics-informed neural networks (PINN) that integrate relevant physics into machine learning models. PINN have shown promise in approximating the solutions to the Navier–Stokes equations, overcoming the limitations of traditional numerical discretization methods. However, challenges such as local minima and long training times persist, motivating the exploration of domain decomposition techniques to improve it. Previous domain decomposition models have introduced spatial and temporal domain decompositions but have yet to fully address issues of smoothness and regularity of global solutions. In this study, we present a novel domain decomposition approach for PINN, termed domain-discretized PINN (DD-PINN), which incorporates complementary loss functions, subdomain-specific transformer networks (TRF), and independent optimization within each subdomain. By enforcing continuity and differentiability through interface constraints and leveraging the Sobolev (H
1) norm of the mean squared error (MSE), rather than the Euclidean norm (L
2), DD-PINN enhances solution regularity and accuracy. The inclusion of TRF in each subdomain facilitates feature extraction and improves convergence rates, as demonstrated through simulations of threetest problems: steady-state flow in a two-dimensional lid-driven cavity, the time-dependent cylinder wake, and the viscous Burgers equation. Numerical comparisons highlight the effectiveness of DD-PINN in preserving global solution regularity and accurately approximating complex phenomena, marking a significant advancement over previous domain decomposition methods within the PINN framework.
Industrial zone-based harmful gas sensor using pure WS2 via doping transition metals (Co, Ni) - a DFT approach
Authors: Poornimadevi C , Preferencial Kala C , John Thiruvadigal D 
Published: June 2024

Abstract
Tungsten disulphide (WS2) has received a lot of interest for its usage in a variety of fields due to its acceptable bandgap and various traits/characteristics. Presently, density functional theory (DFT) has been deployed to thoroughly study the adsorption characteristics of gases (NO, NO2, NH3, BCl3, & SO2) on Y-WS2 (Y = Co, Ni) by determining the adsorption distance, adsorption energy, electron difference density, charge transfer, electron localisation function, recovery time, & work function, also by comparing the band structure, the density of states and the projected density of states. Our results show that Y-WS2 has better conductivity and enormous charge transfer than pure WS2. Additionally, the Y-WS2 exhibits stronger adsorption of more than −0.5 eV for the harmful gases NO2, BCl3, and SO2. Subsequently, for Y-WS2, there is electron localisation overlap only for the BCl3 gas adsorbed system, which highlights the chemisorption character of the gases. Due to the high adsorption energy, Y-WS2 takes a longer time to recover NO2, BCl3, and SO2 gases at ambient temperature. However, by raising the temperature to 673 K, we can quickly recover these molecules from Y-WS2 in a few microseconds. We came to the conclusion that Y-WS2 is the right approach for NO2, BCl3, and SO2 gas-sensing applications.