arXiv: Applied Physics最新文献_第9页

Sensitivity of topological edge states in a non-Hermitian dimer chain 非厄米二聚体链拓扑边态的敏感性

arXiv: Applied Physics Pub Date : 2020-07-07 DOI: 10.1364/PRJ.413873

Zhiwei Guo, Tengzhou Zhang, Juan Song, Haitao Jiang, Hong Chen

{"title":"Sensitivity of topological edge states in a non-Hermitian dimer chain","authors":"Zhiwei Guo, Tengzhou Zhang, Juan Song, Haitao Jiang, Hong Chen","doi":"10.1364/PRJ.413873","DOIUrl":"https://doi.org/10.1364/PRJ.413873","url":null,"abstract":"Photonic topological edge states in one-dimensional dimer chains have long been thought to be robust to structural perturbations by mapping the topological Su-Schrieffer-Heeger model of a solid-state system. However, the edge states at the two ends of a finite topological dimer chain will interact as a result of near-field coupling. This leads to deviation from topological protection by the chiral symmetry from the exact zero energy, weakening the robustness of the topological edge state. With the aid of non-Hermitian physics, the splitting frequencies of edge states can be degenerated again and topological protection recovered by altering the gain or loss strength of the structure. This point of coalescence is known as the exceptional point (EP). The intriguing physical properties of EPs in topological structures give rise to many fascinating and counterintuitive phenomena. In this work, based on a finite non-Hermitian dimer chain composed of ultra-subwavelength resonators, we propose theoretically and verify experimentally that the sensitivity of topological edge states is greatly affected when the system passes through the EP. Using the EP of a non-Hermitian dimer chain, we realize a new sensor that is sensitive to perturbation at the end of the structure and yet topologically protected from internal perturbation. Our demonstration of a non-Hermitian topological structure with an EP paves the way for the development of novel sensors that are not sensitive to internal manufacturing errors but are highly sensitive to changes in the external environment.","PeriodicalId":8423,"journal":{"name":"arXiv: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82966994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 21

Intrinsic-polarization origin of photoconductivity in MAPbI3thin films mapbi3薄膜中光电导电性的本征极化来源

arXiv: Applied Physics Pub Date : 2020-07-05 DOI: 10.1063/5.0046997

R. Saraf, C. Saguy, V. Maheshwari, Hemaprabha Elangovan, Y. Ivry

{"title":"Intrinsic-polarization origin of photoconductivity in MAPbI3thin films","authors":"R. Saraf, C. Saguy, V. Maheshwari, Hemaprabha Elangovan, Y. Ivry","doi":"10.1063/5.0046997","DOIUrl":"https://doi.org/10.1063/5.0046997","url":null,"abstract":"Hybrid-halide perovskite (HHP) films exhibit exceptional photo-electric properties. These materials are utilized for highly efficient solar cells and photoconductive technologies. Both ion migration and polarization have been proposed as the source of enhanced photoelectric activity, but the exact origin of these advantageous device properties has remained elusive. Here, we combined microscale and device-scale characterization to demonstrate that polarization-assisted conductivity governs photoconductivity in thin HHP films. Conductive atomic force microscopy under light and variable temperature conditions showed that the photocurrent is directional and is suppressed at the tetragonal-to-cubic transformation. It was revealed that polarization-based conductivity is enhanced by light, whereas dark conductivity is dominated by non-directional ion migration, as was confirmed by large-scale device measurements. Following the non-volatile memory nature of polarization domains, photoconductive memristive behavior was demonstrated. Understanding the origin of photoelectric activity in HHP allows designing devices with enhanced functionality and lays the grounds for photoelectric memristive devices.","PeriodicalId":8423,"journal":{"name":"arXiv: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76526220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Current-Induced Magnetization Switching of Exchange-Biased NiO Heterostructures Characterized by Spin-Orbit Torque 用自旋-轨道转矩表征交换偏置NiO异质结构的电流感应磁化开关

arXiv: Applied Physics Pub Date : 2020-07-04 DOI: 10.1103/PHYSREVAPPLIED.15.014017

K. Grochot, Łukasz Karwacki, S. Łazarski, Witold Skowro'nski, J. Kanak, Wieslaw Powro'znik, P. Kuświk, M. Kowacz, F. Stobiecki, T. Stobiecki

引用次数: 5

A four-state magnetic tunnel junction switchable with spin–orbit torques 具有自旋轨道转矩可切换的四态磁隧道结

arXiv: Applied Physics Pub Date : 2020-07-03 DOI: 10.1063/5.0014771

Shubhankar Das, Ariel Zaig, M. Schultz, S. Cardoso, D. Leitao, L. Klein

引用次数: 3

On the Validity of Physical Optics for Narrow-band Beam Scattering and Diffraction from the Open Cylindrical Surface 物理光学对开柱面窄带光束散射和衍射的有效性研究

arXiv: Applied Physics Pub Date : 2020-07-01 DOI: 10.2529/PIERS060906142312

Shaolin Liao

引用次数: 12

Beam-Shaping PEC Mirror Phase Corrector Design 波束整形PEC镜相位校正器设计

arXiv: Applied Physics Pub Date : 2020-07-01 DOI: 10.2529/PIERS061005101313

Shaolin Liao

引用次数: 12

Large-area printing of ferroelectric surface and super-domains for efficient solar water splitting 用于高效太阳能水分解的铁电表面和超畴大面积印刷

arXiv: Applied Physics Pub Date : 2020-07-01 DOI: 10.21203/rs.3.rs-36437/v1

Yu Tian, Yaqing Wei, Minghui Pei, R. Cao, Zhenao Gu, Jing Wang, Kunhui Liu, Dashan Shang, J. Niu, Xiaoqiang An, R. Long, Jinxing Zhang

{"title":"Large-area printing of ferroelectric surface and super-domains for efficient solar water splitting","authors":"Yu Tian, Yaqing Wei, Minghui Pei, R. Cao, Zhenao Gu, Jing Wang, Kunhui Liu, Dashan Shang, J. Niu, Xiaoqiang An, R. Long, Jinxing Zhang","doi":"10.21203/rs.3.rs-36437/v1","DOIUrl":"https://doi.org/10.21203/rs.3.rs-36437/v1","url":null,"abstract":"\u0000 Surface electronic structures of the photoelectrodes determine the activity and efficiency of the photoelectrochemical water splitting, but the controls of their surface structures and interfacial chemical reactions remain challenging. Here, we use ferroelectric BiFeO3 as a model system to demonstrate an efficient and controllable water splitting reaction by large-area constructing the hydroxyls-bonded surface. The up-shift of band edge positions at this surface enables and enhances the interfacial holes and electrons transfer through the hydroxyl-active-sites, leading to simultaneously enhanced oxygen and hydrogen evolutions. Furthermore, printing of ferroelectric super-domains with microscale checkboard up/down electric fields separates the distribution of reduction/oxidation catalytic sites, enhancing the charge separation and giving rise to an order of magnitude increase of the photocurrent. This large-area printable ferroelectric surface and super-domains offer an alternative platform for controllable and high-efficient photocatalysis.","PeriodicalId":8423,"journal":{"name":"arXiv: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90169573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

High-acoustic-index-contrast phononic circuits: Numerical modeling 高声学指数对比声子电路:数值模拟

arXiv: Applied Physics Pub Date : 2020-06-29 DOI: 10.1063/5.0019584

Wance Wang, Mohan Shen, Chang-ling Zou, Wei Fu, Zhen Shen, H. Tang

{"title":"High-acoustic-index-contrast phononic circuits: Numerical modeling","authors":"Wance Wang, Mohan Shen, Chang-ling Zou, Wei Fu, Zhen Shen, H. Tang","doi":"10.1063/5.0019584","DOIUrl":"https://doi.org/10.1063/5.0019584","url":null,"abstract":"We numerically model key building blocks of a phononic integrated circuit that enable phonon routing in high-acoustic-index waveguides. Our particular focus is on Gallium Nitride-on-sapphire phononic platform which has recently demonstrated high acoustic confinement in its top layer without the use of suspended structures. We start with systematic simulation of various transverse phonon modes supported in strip waveguides and ring resonators with sub-wavelength cross-section. Mode confinement and quality factors of phonon modes are numerically investigated with respect to geometric parameters. Quality factor up to $10^{8}$ is predicted in optimized ring resonators. We next study the design of the phononic directional couplers, and present key design parameters for achieving strong evanescent couplings between modes propagating in parallel waveguides. Last, interdigitated transducer electrodes are included in the simulation for direct excitation of a ring resonator and critical coupling between microwave input and phononic dissipation. Our work provides comprehensive numerical characterization of phonon modes and functional phononic components in high-acoustic-index phononic circuits, which supplements previous theories and contributes to the emerging field of phononic integrated circuits.","PeriodicalId":8423,"journal":{"name":"arXiv: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78267998","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 13

Mechanical Evaluation of Selective Laser Melted Ni-Rich NiTi: Compression, Tension, and Torsion 选择性激光熔化富镍NiTi的力学评价:压缩、拉伸和扭转

arXiv: Applied Physics Pub Date : 2020-06-28 DOI: 10.1115/MSEC2020-8432

K. S. Baghbaderani, M. Nematollahi, Parisa Bayatimalayeri, Hediyeh Dabbaghi, Ahmadreza Jahadakbar, M. Elahinia

{"title":"Mechanical Evaluation of Selective Laser Melted Ni-Rich NiTi: Compression, Tension, and Torsion","authors":"K. S. Baghbaderani, M. Nematollahi, Parisa Bayatimalayeri, Hediyeh Dabbaghi, Ahmadreza Jahadakbar, M. Elahinia","doi":"10.1115/MSEC2020-8432","DOIUrl":"https://doi.org/10.1115/MSEC2020-8432","url":null,"abstract":"Two unique behaviors of superelasticity and shape memory effect have made shape memory alloy such as NiTi, an interesting alloy for different applications. Recently, additive manufacturing (AM) as a powerful tool for fabricating NiTi has become of interest to make complex geometries. Selective laser melting (SLM) is an AM method that not only provides flexibility to make complex 3D shapes but also it can be possible to tailor the thermomechanical properties of the parts just by changing the process parameters. The non-homogeneous microstructure of as-fabricated parts as well as asymmetric mechanical behavior of NiTi, make it important to study the properties of SLM NiTi parts under different loading condition. In this study, Ni50.8Ti (at. %) powder was utilized to fabricate cube, dog-bone, and tube by SLM technique. The transformation temperatures (TTs) of samples were measured by the differential scanning calorimetry (DSC) method and the variation of TTs was discussed. Three coupons were tested mechanically under compression, tension, and torsion. In-situ digital image correlation (DIC) was employed to measure and monitor the strain field of samples during the mechanical tests. The strain distribution showed localized strain for all three samples. The equivalent stress/strain was calculated to compare the result of compressive, tensile, and torsional responses and the significant asymmetric behavior was shown and discussed.","PeriodicalId":8423,"journal":{"name":"arXiv: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81291542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6

Arbitrary manipulations of dual harmonics and their wave behaviors based on space-time-coding digital metasurface 基于空时编码数字超表面的对偶谐波任意操纵及其波动行为

arXiv: Applied Physics Pub Date : 2020-06-26 DOI: 10.1063/5.0017885

J. Dai, Jin Yang, Wan-Chun Tang, Ming Zheng Chen, J. Ke, Q. Cheng, Shi Jin, T. Cui

{"title":"Arbitrary manipulations of dual harmonics and their wave behaviors based on space-time-coding digital metasurface","authors":"J. Dai, Jin Yang, Wan-Chun Tang, Ming Zheng Chen, J. Ke, Q. Cheng, Shi Jin, T. Cui","doi":"10.1063/5.0017885","DOIUrl":"https://doi.org/10.1063/5.0017885","url":null,"abstract":"Space-time modulated metasurfaces have attracted significant attention due to the additional degree of freedom in manipulating the electromagnetic (EM) waves in both space and time domains. However, the existing techniques have limited wave control capabilities, leading to just a few feasible schemes like regulation of only one specific harmonic. Here, we propose to realize independent manipulations of arbitrarily dual harmonics and their wave behaviors using a space-time-coding (STC) digital metasurface. By employing different STC sequences to the reflection phase of the metasurface, independent phase-pattern configurations of two desired harmonics can be achieved simultaneously, which further leads to independent beam shaping at the two harmonic frequencies. An analytical theory is developed to offer the physical insights in the arbitrary dual-harmonic manipulations of spectra and spatial beams, which is verified by experiments with good agreements. The presented STC strategy provides a new way to design multifunctional programmable systems, which will find potential applications such as cognitive radar and multi-user wireless communications.","PeriodicalId":8423,"journal":{"name":"arXiv: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88935845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 30