bluuebunny/crossref_metadata_2025_split huggingface dataset:
A perspective on the physical scaling down of hafnia-based ferroelectrics
Authors: Park Ju Yong , Lee Dong Hyun , Park Geun Hyeong , Lee Jaewook , Lee Younghwan , Park Min Hyuk 
Published: February 2023

Abstract
HfO2-based ferroelectric thin films have attracted significant interest for semiconductor device applications due to their compatibility with complementary metal oxide semiconductor (CMOS) technology. One of the benefits of HfO2-based ferroelectric thin films is their ability to be scaled to thicknesses as low as 10 nm while retaining their ferroelectric properties; a feat that has been difficult to accomplish with conventional perovskite-based ferroelectrics using CMOS-compatible processes. However, reducing the thickness limit of HfO2-based ferroelectric thin films below the sub 5 nm thickness regime while preserving their ferroelectric property remains a formidable challenge. This is because both the structural factors of HfO2, including polymorphism and orientation, and the electrical factors of HfO2-based devices, such as the depolarization field, are known to be highly dependent on the HfO2 thickness. Accordingly, when the thickness of HfO2 drops below 5 nm, these factors will become even more crucial. In this regard, the size effect of HfO2-based ferroelectric thin films is thoroughly discussed in the present review. The impact of thickness on the ferroelectric property of HfO2-based thin films and the electrical performance of HfO2-based ferroelectric semiconductor devices, such as ferroelectric random-access-memory, ferroelectric field-effect-transistor, and ferroelectric tunnel junction, is extensively discussed from the perspective of fundamental theory and experimental results. Finally, recent developments and reports on achieving ferroelectric HfO2 at sub-5 nm thickness regime and their applications are discussed.
A compound Kinoform/Fresnel zone plate lens with 15 nm resolution and high efficiency in soft x-ray
Authors: Tong Xujie , Chen Yifang , Mu Chengyang , Chen Qiucheng , Zhang Xiangzhi , Zeng Guang , Li Yuchun , Xu Zijian , Zhao Jun , Zhen Xiangjun , Mao Chengwen , Lu Hongliang , Tai Renzhong 
Published: February 2023

Abstract
X-ray microscope as an important nanoprobing tool plays a prevailing role in nano-inspections of materials. Despite the fast advances of high resolution focusing/imaging reported, the efficiency of existing high-resolution zone plates is mostly around 5% in soft x-ray and rapidly goes down to 1%–2% when the resolution approaches 10 nm. It is well known that the rectangular zone shape, beamstop, limited height/width ratios, material absorption of light and structural defects are likely responsible for the limited efficiency. Although zone plates with Kinoform profile are supposed to be efficient, progress for achieving both high resolution (<30 nm) and high efficiency (>5%) have hardly been addressed in soft x-ray. In this work, we propose a compound Kinoform/Fresnel zone plate (CKZP) by combing a dielectric Kinoform zone plate with a 15 nm resolution zone plate. Greyscale electron beam lithography was applied to form the 3D Kinoform zone plate and atomic layer deposition was carried out to form the binary zone plate. Optical characterizations demonstrated 15 nm resolution focusing/imaging with over 7.8% efficiency in soft x-ray. The origin of the efficiency improvement behind the proposed compound lens is theoretically analyzed and discussed.
A route for the top-down fabrication of ordered ultrathin GaN nanowires
Authors: Oliva M , Kaganer V , Pudelski M , Meister S , Tahraoui A , Geelhaar L , Brandt O , Auzelle T 
Published: February 2023

Abstract
We introduce a facile route for the top-down fabrication of ordered arrays of GaN nanowires with aspect ratios exceeding 10 and diameters below 20 nm. Highly uniform thin GaN nanowires are first obtained by lithographic patterning a bilayer Ni/SiN
x
hard mask, followed by a combination of dry and wet etching in KOH. The SiN
x
is found to work as an etch stop during wet etching, which eases reproducibility. Arrays with nanowire diameters down to (33 ± 5) nm can be achieved with a uniformity suitable for photonic applications. Next, a scheme for digital etching is demonstrated to further reduce the nanowire diameter down to 5 nm. However, nanowire breaking or bundling is observed for diameters below ≈20 nm, an effect that is associated to capillary forces acting on the nanowires during sample drying in air. Explicit calculations of the nanowire buckling states under capillary forces indicate that nanowire breaking is favored by the incomplete wetting of water on the substrate surface during drying. The observation of intense nanowire photoluminescence at room-temperature indicates good compatibility of the fabrication route with optoelectronic applications. The process can be principally applied to any GaN/SiN
x
nanostructures and allows regrowth after removal of the SiN
x
mask.
Rigorous bounds on Lyapunov exponents of linked twist maps
Authors: Wright Patrick , Niesen Jitse , Sturman Rob 
Published: February 2023

Abstract
Rigorous, elementary upper and lower bounds upon the Lyapunov exponents of a parametrised family of linked twist maps are given, and obtained explicitly for a specific range of parameter values. The method used to obtain the bounds utilises the existence of invariant cones for specific products of the underlying family of shear maps, and the return time partition of the overlap region of the two annuli. Improvements upon the accuracy of this method are then obtained by considering preceding sequences of matrices on the orbits.
Radial and non-radial multiple solutions to a general mixed dispersion NLS equation
Authors: d’Avenia Pietro , Pomponio Alessio , Schino Jacopo 
Published: February 2023

AbstractWe study the following nonlinear Schrödinger equation with a fourth-order dispersion termΔ2u−βΔu=g(u)in RNin the positive and zero mass regimes: in the former,N⩾2andβ>−2m, wherem > 0 depends ong; in the latter,N⩾3andβ > 0. In either regimes, we find an infinite sequence of solutions under rather generic assumptions aboutg; ifN = 2 in the positive mass case, orN = 4 in the zero mass case, we need to strengthen such assumptions. Our approach is variational.
3D pyramidal densely connected network with cross-frame uncertainty guidance for intravascular ultrasound sequence segmentation
Authors: Xia Menghua , Yang Hongbo , Huang Yi , Qu Yanan , Zhou Guohui , Zhang Feng , Wang Yuanyuan , Guo Yi 
Published: February 2023

Abstract

Objective. Automatic extraction of external elastic membrane border (EEM) and lumen-intima border (LIB) in intravascular ultrasound (IVUS) sequences aids atherosclerosis diagnosis. Existing IVUS segmentation networks ignored longitudinal relations among sequential images and neglected that IVUS images of different vascular conditions vary largely in intricacy and informativeness. As a result, they suffered from performance degradation in complicated parts in IVUS sequences. Approach. In this paper, we develop a 3D Pyramidal Densely-connected Network (PDN) with Adaptive learning and post-Correction guided by a novel cross-frame uncertainty (CFU). The proposed method is named PDN-AC. Specifically, the PDN enables the longitudinal information exploitation and the effective perception of size-varied vessel regions in IVUS samples, by pyramidally connecting multi-scale 3D dilated convolutions. Additionally, the CFU enhances the robustness of the method to complicated pathology from the frame-level (f-CFU) and pixel-level (p-CFU) via exploiting cross-frame knowledge in IVUS sequences. The f-CFU weighs the complexity of IVUS frames and steers an adaptive sampling during the PDN training. The p-CFU visualizes uncertain pixels probably misclassified by the PDN and guides an active contour-based post-correction. Main results. Human and animal experiments were conducted on IVUS datasets acquired from atherosclerosis patients and pigs. Results showed that the f-CFU weighted adaptive sampling reduced the Hausdorff distance (HD) by 10.53%/7.69% in EEM/LIB detection. Improvements achieved by the p-CFU guided post-correction were 2.94%/5.56%. Significance. The PDN-AC attained mean Jaccard values of 0.90/0.87 and HD values of 0.33/0.34 mm in EEM/LIB detection, preferable to state-of-the-art IVUS segmentation methods.
Minimizing separatrix crossings through isoprominence
Authors: Burby J W , Duignan N , Meiss J D 
Published: February 2023

Abstract
A simple property of magnetic fields that minimizes bouncing to passing type transitions of guiding center orbits is defined and discussed. This property, called isoprominence, is explored through the framework of a near-axis expansion. It is shown that isoprominent magnetic fields for a toroidal configuration exist to all orders in a formal expansion about a magnetic axis. Some key geometric features of these fields are described.
Discrete-modulation continuous-variable quantum key distribution with a high key rate
Authors: Wang Pu , Zhang Yu , Lu Zhenguo , Wang Xuyang , Li Yongmin 
Published: February 2023

Abstract
Discrete-modulation continuous-variable (CV) quantum key distribution has the potential for large-scale deployment in secure quantum communication networks owing to its low implementation complexity and compatibility with the current coherent optical telecommunication. However, current discrete-modulation protocols require relatively large constellation sizes to achieve a key rate comparable to that of the Gaussian modulation. Here, we show that a high key rate comparable to the Gaussian modulation can be achieved using only ten or so coherent states by implementing suitable key map and numerical convex optimization techniques. Specifically, the key rate of the two-ring constellation with 12 coherent states (four states in the inner ring and eight states in the outer ring) can reach 2.4 times of that of original quadrature phase shift keying and 70% of the Gaussian modulation protocol at 50 km. Such an approach can easily be applied to existing systems, making the discrete-modulation protocol an attractive alternative for high-rate and low-cost applications in secure quantum communication networks.
New modied Atangana-Baleanu fractional derivative applied to solve nonlinear fractional dierential equations
Authors: Yépez-Martínez H , Gómez-Aguilar J F , Inc Mustafa 
Published: February 2023

Abstract
The main goal of this work is to present a new modified version of the Atangana-Baleanu fractional derivative with Mittag-Leffler non-singular kernel and strong memory. This proposal presents important advantages when specific initial conditions are impossed. The new modified version of the Atangana-Baleanu fractional derivative with Mittag-Leffler non-singular kernel has been constructed considering the fulfillment of the initial conditions with special interest because they are decisive in the obtaintion of analytical and numerical solutions of the fractional differential equations. The advantage of this new fractional derivative in the fulfilling of initial conditions plays a central role for the implementation of different perturbative analytical methods, such as the homotopy perturbation method and the modified homotopy perturbation method. These methods will be applied to solve nonlinear fractional differential equations. This novel modified derivative can be applied in the future in different mathematical modeling areas where satisfy the initial conditions is of great relevance to get more accurate description of real-world problems.
The effect of sample viscoelastic properties and cantilever amplitudes on maximum repulsive force, indentation, and energy dissipation in bimodal AFM
Authors: Damircheli Mehrnoosh , Jung Uidam , Wagner Ryan 
Published: February 2023

Abstract
Bimodal atomic force microscopy (AFM) uses two eigenfrequencies to map nanomechanical properties with high spatial and temporal resolution. To reliably map surface properties and to understand the links between experimental observables, energy dissipation, and viscoelastic properties considering the effects of nonconservative interaction forces is essential. To avoid damaging the sample, the maximum force between the tip and the surface and the maximum indentation of the tip into the sample needs to be controlled. In this work, we use both experiments and simulations to study how viscoelastic properties affect the cantilever response in bimodal AFM. We simulate the tip-sample interaction force, indentation, and energy dissipation for samples with different viscous properties. Under the tested operating conditions, we observe that more energy is dissipated in the higher eigenmode. The larger higher eigenmode free amplitude increases the energy dissipation in both eigenmodes. The larger energy dissipation increases the contrast of the bimodal AFM dissipation map. The simulations are cross-compared with experiments and similar trends are observed. This work is important for understanding and optimizing bimodal AFM measurements on samples with significant viscoelastic responses, such as cells, tissues, and polymers.
Phonon dynamics in lead free perovskite (1-x)KNN-xBAN (x = 0.0–0.1): a temperature dependent raman study
Authors: Anjali Anjali , Kumar Deepu , Dwivedi Sushmita , Kumar Sunil , Kumar Pradeep 
Published: February 2023

Abstract
K0.5Na0.5NbO3 (KNN) has been under extensive focus in recent times due to it being an alternative to lead-free multifunctional materials and properties like room temperature ferroelectricity, stability in air and technology friendly applications. In this work, we report a comprehensive temperature dependent, compositional change induced structural variation and polarization dependent Raman spectroscopy on BaAl0.5Nb0.5O3 (BAN) doped KNN in the spectral range of 10–1000 cm−1. Multiple phase transitions are marked by the strong renormalization of the phonon self-energy parameters, i.e. mode frequencies and linewidths, in the temperature range of 83 K to 623 K. Change in the phase transition temperature is tracked via phonon anomalies with varying doping concentration, x = 0.0, 0.02, 0.05, 0.07 and 0.1, and is found to be as large as ∼100 K for orthorhombic to tetragonal phase transition for x = 0.1. Raman extracted phase diagram shows that the stability of the ferroelectric orthorhombic phase in the vicinity of room temperature increases with the increasing doping concentration. Also, from our polarization-dependent measurements we could decipher the symmetry of the observed phonon modes for KNN system.
The Near Infrared Imager and Slitless Spectrograph for JWST. V. Kernel Phase Imaging and Data Analysis
Authors: Kammerer Jens , Cooper Rachel A. , Vandal Thomas , Thatte Deepashri , Martinache Frantz , Sivaramakrishnan Anand , Chaushev Alexander , Stolker Tomas , Lloyd James P. , Albert Loïc , Doyon René , Sallum Steph , Perrin Marshall D. , Pueyo Laurent , Mérand Antoine , Gallenne Alexandre , Greenbaum Alexandra , Sanchez-Bermudez Joel , Blakely Dori , Johnstone Doug , Volk Kevin , Martel Andre , Goudfrooij Paul , Meyer Michael R. , Willott Chris J. , Furio Matthew De , Dang Lisa , Radica Michael , Noirot Gaël 
Published: February 2023

Abstract
Kernel phase imaging (KPI) enables the direct detection of substellar companions and circumstellar dust close to and below the classical (Rayleigh) diffraction limit. The high-Strehl full pupil images provided by the James Webb Space Telescope (JWST) are ideal for application of the KPI technique. We present a kernel phase analysis of JWST NIRISS full pupil images taken during the instrument commissioning and compare the performance to closely related NIRISS aperture masking interferometry (AMI) observations. For this purpose, we develop and make publicly available the custom Kpi3Pipeline data reduction pipeline enabling the extraction of kernel phase observables from JWST images. The extracted observables are saved into a new and versatile kernel phase FITS file data exchange format. Furthermore, we present our new and publicly available fouriever toolkit which can be used to search for companions and derive detection limits from KPI, AMI, and long-baseline interferometry observations while accounting for correlated uncertainties in the model fitting process. Among the four KPI targets that were observed during NIRISS instrument commissioning, we discover a low-contrast (∼1:5) close-in (∼1 λ/D) companion candidate around CPD-66 562 and a new high-contrast (∼1:170) detection separated by ∼1.5 λ/D from 2MASS J062802.01-663738.0. The 5σ companion detection limits around the other two targets reach ∼6.5 mag at ∼200 mas and ∼7 mag at ∼400 mas. Comparing these limits to those obtained from the NIRISS AMI commissioning observations, we find that KPI and AMI perform similar in the same amount of observing time. Due to its 5.6 times higher throughput if compared to AMI, KPI is beneficial for observing faint targets and superior to AMI at separations ≳325 mas. At very small separations (≲100 mas) and between ∼250 and 325 mas, AMI slightly outperforms KPI which suffers from increased photon noise from the core and the first Airy ring of the point-spread function.
The Unistellar Exoplanet Campaign: Citizen Science Results and Inherent Education Opportunities
Authors: O’Conner Peluso Daniel , Esposito Thomas M. , Marchis Franck , Dalba Paul A. , Sgro Lauren , Megowan-Romanowicz Colleen , Pennypacker Carl , Carter Bradley , Wright Duncan , Avsar Arin M. , Perrocheau Amaury 
Published: February 2023

Abstract
This paper presents early results from and prospects for exoplanet science using a citizen science private/public partnership observer network managed by the SETI Institute in collaboration with Unistellar. The network launched in 2020 January and includes 163 citizen scientist observers across 21 countries. These observers can access a citizen science mentoring service developed by the SETI Institute and are also equipped with Unistellar Enhanced Vision Telescopes. Unistellar technology and the campaign’s associated photometric reduction pipeline enable each telescope to readily obtain and communicate light curves to observers with signal-to-noise ratio suitable for publication in research journals. Citizen astronomers of the Unistellar Exoplanet (UE) Campaign routinely measure transit depths of ≳1% and contribute their results to the exoplanet research community. The match of the detection system, targets, and scientific and educational goals is robust. Results to date include 281 transit detections out of 651 processed observations. In addition to this campaign’s capability to contribute to the professional field of exoplanet research, UE endeavors to drive improved science, technology, engineering, and mathematics education outcomes by engaging students and teachers as participants in science investigations, that is, learning science by doing science.
Multiwavelength Analysis of a Nearby Heavily Obscured AGN in NGC 449
Authors: Guo Xiaotong , Gu Qiusheng , Xu Jun , Fang Guanwen , Ge Xue , Chen Yongyun , Yu Xiaoling , Ding Nan 
Published: February 2023

Abstract
We present the multiwavelength analysis of a heavily obscured active galactic nucleus (AGN) in NGC 449. We first constructed a broadband X-ray spectrum using the latest NuSTAR and XMM-Newton data. Its column density (≃1024 cm−2) and photon index (Γ ≃ 2.4) were reliably obtained by analyzing the broadband X-ray spectrum. However, the scattering fraction and the intrinsic X-ray luminosity could not be well constrained. Combined with the information obtained from the mid-infrared spectrum and spectral energy distribution fitting, we derived its intrinsic X-ray luminosity (≃8.54 × 1042 erg s−1) and scattering fraction (f
scat ≃ 0.26%). In addition, we also derived the following results. (1) The mass accretion rate of the central AGN is about 2.54 × 10−2
M
⊙ yr−1, and the Eddington ratio is 8.39 × 10−2. (2) The torus of this AGN has a high gas-to-dust ratio (N
H/A

V
= 8.40 × 1022 cm−2 mag−1). (3) The host galaxy and central AGN are both in the early stage of coevolution.
Astrometric Reduction of Saturnian Satellites with Cassini-ISS Images Degraded by Trailed Stars
Authors: Zhang Qing-Feng , Liu Meng-Qi , Li Yan , Wu Lin-Peng , Wang Zhi-Qiang , Zhu Li-Sha , Li Zhan 
Published: February 2023

Abstract
The Imaging Science Subsystem (ISS) mounted on the Cassini spacecraft has taken a lot of images, which provides an important source of high-precision astrometry of some planets and satellites. However, some of these images are degraded by trailed stars. Previously, these degraded images cannot be used for astrometry. In this paper, a new method is proposed to detect and compute the centers of these trailed stars automatically. The method is then performed on the astrometry of ISS images with trailed stars. Finally, we provided 658 astrometric positions between 2004 and 2017 of several satellites that include Enceladus, Dione, Tethys, Mimas and Rhea. Compared with the JPL ephemeris SAT427, the mean residuals of these measurements are 0.11 km and 0.26 km in R.A. and decl., respectively. Their standard deviations are 1.08 km and 1.37 km, respectively. The results show that the proposed method performs astrometric measurements of Cassini ISS images with trailed stars effectively.
First Detailed Analysis of a Relatively Deep, Low Mass-ratio Contact Binary: ATO J108.6991+27.8306
Authors: Ma Shuo , Liu Jinzhong , Zhang Yu , Lü Guoliang , Wu Ting , He Chenyang 
Published: February 2023

Abstract
We present the first detailed photometric analysis of ATO J108.6991+27.8306 (hereinafter as J108). The short-period close binary J108 was observed by the Nanshan 1 m Wide Field Telescope of the Xinjiang Astronomical Observatory. The obtained BVRI-band light curves were used to determine the photometric solution by using the 2003 version of the Wilson-Devinney code. J108 is a typical deep (f > 50%), low mass ratio (q < 0.25) overcontact binary system with a mass ratio of q = 0.1501 and a fill-out factor of f = 50.1 %, suggesting that it is in the late evolutionary stage of contact binary systems. We found the target to be a W-type W UMa binary and provided evidence for the presence of starspots on both components. From the temperature-luminosity diagram, the main component is the evolved main sequence star with an evolutionary age of about 7.94 Gyr.
Decoherence: a numerical study
Authors: Nagele Chris , Janssen Oliver , Kleban Matthew 
Published: February 2023

Abstract
We study quantum decoherence numerically in a system consisting of a relativistic quantum field theory coupled to a measuring device that is itself coupled to an environment. The measuring device and environment are treated as quantum, non-relativistic particles. We solve the Schrödinger equation for the wave function of this tripartite system using exact diagonalization. Although computational limitations on the size of the Hilbert space prevent us from exploring the regime where the device and environment consist of a truly macroscopic number of degrees of freedom, we nevertheless see clear evidence of decoherence: after tracing out the environment, the density matrix describing the system and measuring device evolves quickly towards a matrix that is close to diagonal in a subspace of pointer states. We measure the speed with which decoherence spreads in the relativistic quantum field theory for a range of parameters. We find that it is less than the speed of light but faster than the speed of the massive charges in the initial state.