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arXiv 2023年

作者： Liu, Yuanfeng Zhou, Le Guo, Mengfan Xu, Zongqi Ma, Jing Wen, Yongzheng Litchinitser, Natalia M. Shen, Yang Sun, Jingbo Zhou, Ji School of Materials Science and Engineering Tsinghua University Beijing100084 China Department of Electrical and Computer Engineering Duke University DurhamNC27708 United States

The structural symmetry of solids plays an important role in defining their linear and nonlinear optical properties. The quest for versatile, cost-effective, large-scale, and defect-free approaches and materials platforms for tailoring structural and optical properties on demand has been underway for decades. We experimentally demonstrate a bottom-up self-assembly-based organic engineered material comprised of synthesized molecules with large dipole moments that are crystallized into a spherulite structure. The molecules align in an azimuthal direction, resulting in a vortex polarity with spontaneously broken symmetry leading to strong optical anisotropy and nonlinear optical responses. These unique polarization properties of the judiciously designed organic spherulite combined with the symmetry of structured optical beams enable a plethora of new linear and nonlinear light-matter interactions, including the generation of optical vortex beams with complex spin states and on-demand topological charges at the fundamental, doubled, and tripled frequencies. The results of this work are likely to enable numerous applications in areas such as high-dimensional quantum information processing, with large capacity and high security. The demonstrated spherulite crystals facilitate stand-alone micro-scale devices that rely on the unique micro-scale spontaneous vortex polarity that is likely to enable future applications for high-dimensional quantum information processing, spatiotemporal optical vortices, and a novel platform for optical manipulation and trapping. Copyright © 2023, The Authors. All rights reserved.

关键词： Vortex flow

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Enhancing memristor performance with 2D SnO_(x)/SnS_(2) heterostructure forneuromorphic computing

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science China materials 2025年第2期68卷 581-589页

作者： Yangwu Wu Sifan Li Yun Ji Zhengjin Weng Houying Xing Lester Arauz Travis Hu Jinhua Hong Kah-Wee Ang Song Liu State Key Laboratory of Chemo/Biosensing and Chemometrics College of Chemistry and Chemical EngineeringHunan UniversityChangsha 410082China Department of Electrical and Computer Engineering National University of SingaporeSingapore 117583Singapore Joint International Research Laboratory of Information Display and Visualization School of Electronic Science and EngineeringSoutheast UniversityNanjing 210096China Department of Mechanical Engineering California State UniversityLos Angeles5151 State University DrLos AngelesCA 90032USA College of Materials Science and Engineering Hunan UniversityChangsha 410082China Shenzhen Research Institute Hunan UniversityShenzhen 518000China

Layered metal dichalcogenides (LMDs) neuromorphic memristor devices offer a promising alternative toconventional von Neumann architectures, addressing speedand energy efficiency constraints. However, challenges remainin controlling resistive switching and operating voltage incrystalline LMD memristors due to environmental stabilization issues, which hinder neural network hardware development. Herein, we introduce an optimization method formemristor operation by controlling oxidation through ozonetreatment, creating a SnO_(x)/SnS_(2) resistive layer. These optimized memristors demonstrate low switching voltages (~1 V),rapid switching speeds (~20 ns), high switching ratios (10^(2)),and the ability to emulate synaptic weight plasticity. Crosssectional transmission electron microscopy and energy-dispersive X-ray spectroscopy identified defects and Ti conductive filaments in the resistive switching layer, contributingto uniform switching and minimized operating variation. Thedevice achieved 90% accuracy in MNIST handwritten recognition, and hardware-based image convolution was successfully implemented, showcasing the potential of SnO_(x)/SnS_(2)memristors for neuromorphic applications.

关键词： SnO_(x)/SnS_(2) oxidation layered metal dichalcogenides convolutional image processing neuromorphic computing

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Time-dependence of SrVO3 thermionic electron emission properties

arXiv

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arXiv 2023年

作者： Sheikh, Md Sariful Jacobs, Ryan Morgan, Dane Booske, John Department of Materials Science and Engineering University of Wisconsin-Madison MadisonWI53706 United States Department of Electrical Engineering and Computer Science University of Wisconsin-Madison MadisonWI53706 United States

Thermionic electron emission cathodes are critical components of various high power and high frequency vacuum electronic devices, electron microscopes, e-beam lithographic devices, and thermionic energy converters, which all demand an efficient and long-lasting low work function cathode. Single phase, polycrystalline perovskite oxide SrVO3, with its intrinsic low effective work function and facile synthesis process, is a promising cathode candidate, where previous works have shown evidence of an effective work function as low as 2.3 eV. However, assessment of the stability over time under conditions relevant for operation and the related interplay of evolving surface chemistry with emission performance are still missing, and necessary for understanding how to best prepare, process and operate SrVO3 cathodes. In this work, we study the vacuum activation process of SrVO3 and find it has promising emission stability over 15 days of continuous high temperature operation. We find that SrVO3 shows surface Sr and O segregation during operation, which we hypothesize is needed to create a positive surface dipole, leading to low effective work function. Emission repeatability from cyclic heating and cooling suggests the promising stability of the low effective work function surface, and additional observations of drift-free emission during one hour of continuous emission testing at high temperature further demonstrates its excellent performance stability. Copyright © 2023, The Authors. All rights reserved.

关键词： Work function

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A Composite TE-TFE-FE Model for Schottky Barrier Reverse Current over the Entire Electric-Field Range

A Composite TE-TFE-FE Model for Schottky Barrier Reverse Cur...

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2022 Device Research Conference, DRC 2022

作者： Li, Wenshen Jena, Debdeep Xing, Huili Grace School of Electrical and Computer Engineering Cornell University IthacaNY14853 United States Cornell University Department of Materials Science and Engineering IthacaNY14853 United States Kavli Institute at Cornell for Nanoscale Science Cornell University IthacaNY14853 United States

ISBN: (数字)9781665498838

ISBN: (纸本)9781665498838

Schottky barriers in wide bandgap (WBG) semiconductors can sustain very large electric fields under reverse bias due to the access of very large barrier heights (>1 eV) and the very high intrinsic breakdown field (>3 MV/cm) of WBG semiconductors [1]. Under high surface electric-fields (E), the ideal reverse-bias leakage current (JR) is dominated by barrier tunneling rather than thermionic emission (TE), thus thermionic-field-emission (TFE) or field-emission (FE) becomes the dominant mechanism [1] [2]. Therefore, to accurately describe the reverse current over the entire surface electric-field range, TFE and FE models are required in addition to the TE model. © 2022 IEEE.

关键词： Thermionic emission

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Broadband Acoustic Meta-structures Fabricated by Additive Manufacturing

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材料导报 2020年第11期34卷 11001-11002页

作者： JIA Xiao HONG Minghui YAN Ming Department of Materials Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Department of Electrical and Computer Engineering National University of Singapore4 Engineering Drive 3117583Singapore

Acoustic meta-structures,because of their flexible and unprecedented proprieties,such as negative dynamic density,negative bulk modulus and refractive index of negative,near-zero or extremely large value,enable new applications to manipulate sound waves propagation and control energy transfer[1].Over the past decades,the development of acoustic meta-structures has not only provided advanced functionalities but also tackled the problem of limited device ***,the meta-structures are explored based on two different kinds of unit cells:locally resonant and non-resonant *** acoustic components with the Helmholtz resonator[2],membrane structure[3]or other structured composites were investigated to realize local *** this circumstance,their resonant behaviors are sensitive to the frequency,where the desirable properties can be obtained in the vicinities of the resonant ***,they suffer from the inherent“narrow band”,resulting in large sound attenuation when the frequency is off *** the non-resonant meta-structures,the unit cell with convoluted waveguides such as space-coiling sound channels[4],labyrinthine[5]or tapered structures[6]were proposed to achieve unusual effective properties over a wider ***,the impedance mismatch between the meta-structure and the environmental fluid leads to a large energy reflection and sound attenuation inside the waveguides due to thermo-viscous loss in the narrow sound ***,it is still an open problem in both industry and academia to optimize the broadband performance of the meta-structure devices.

关键词： narrow sound sizes

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Emergent Ferromagnetism in CaRuO₃/CaMnO₃ (111)-Oriented Superlattices

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Nano Letters 2024年第8期24卷 2567-2573页

作者： Kane, Margaret Bhandari, Churna Holtz, Megan E. Balakrishnan, Purnima P. Grutter, Alexander J. Fitzsimmons, Michael Yang, Chao-Yao Satpathy, Sashi Paudyal, Durga Suzuki, Yuri Department of Materials Science and Engineering Stanford University Stanford 94305 CA United States Ames National Laboratory Iowa State University Ames 50011 IA United States Metallurgical and Materials Engineering Colorado School of Mines Golden 80401 CO United States NIST Center for Neutron Research National Institute of Standards and Technology Gaithersburg 20899 MD United States Neutron Scattering Division Oak Ridge National Laboratory Oak Ridge 37830 TN United States Department of Material Science and Engineering National Yang Ming Chiao Tung University Hsinchu City 30100 Taiwan Department of Physics & Astronomy University of Missouri Columbia 65211 MO United States Department of Applied Physics Stanford University Stanford 94305 CA United States Geballe Laboratory for Advanced Materials Stanford University Stanford 94305 CA United States Department of Electrical and Computer Engineering Iowa State University Ames 50011 IA United States

The boundary between CaRuO3 and CaMnO3 is an ideal test bed for emergent magnetic ground states stabilized through interfacial electron interactions. In this system, nominally antiferromagnetic and paramagnetic materi... 详细信息

The boundary between CaRuO₃ and CaMnO₃ is an ideal test bed for emergent magnetic ground states stabilized through interfacial electron interactions. In this system, nominally antiferromagnetic and paramagnetic materials combine to yield interfacial ferromagnetism in CaMnO₃ due to electron leakage across the interface. In this work, we show that the crystal symmetry at the surface is a critical factor determining the nature of the interfacial interactions. Specifically, by growing CaRuO₃/CaMnO₃ heterostructures along the (111) instead of the (001) crystallographic axis, we achieve a 3-fold enhancement of the magnetization and involve the CaRuO₃ layers in the ferromagnetism, which now spans both constituent materials. The stabilization of a net magnetic moment in CaRuO₃ through strain effects has been long-sought but never consistently achieved, and our observations demonstrate the importance of interface engineering in the development of new functional heterostructures. © 2024 American Chemical Society.

关键词： complex oxides emergent magnetism manganites ruthenatess superlattices

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Reconfigurable Parfocal Zoom Metalens

Reconfigurable Parfocal Zoom Metalens

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CLEO: science and Innovations, S and I 2022

作者： Shalaginov, Mikhail Yang, Fan An, Sensong Lin, Hung I. Stoll, Katherine Kang, Myungkoo Agarwal, Anuradha Richardson, Kathleen Rivero-Baleine, Clara Zhang, Hualiang Hu, Juejun Gu, Tian Department of Materials Science & Engineering Massachusetts Institute of Technology CambridgeMA United States The College of Optics & Photonics Department of Materials Science and Engineering University of Central Florida OrlandoFL United States Missiles and Fire Control Lockheed Martin Corporation OrlandoFL United States Department of Electrical & Computer Engineering University of Massachusetts Lowell LowellMA United States Materials Research Laboratory Massachusetts Institute of Technology CambridgeMA United States

We designed and experimentally realized a non-mechanically tuned metalens capable of performing x 10 zoom while maintaining focus. The metalens consists of two dielectric metasurfaces made of low-loss optical phase-ch... 详细信息

ISBN: (纸本)9781557528209

关键词： Phase change materials

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A mobility study of monolayer MoS2 on low-κ/high-κ dielectrics

A mobility study of monolayer MoS2 on low-κ/high-κ dielect...

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Device Research Conference

作者： Zheng Sun Cindy Chen Joshua A. Robinson Zhihong Chen Joerg Appenzeller School of Electrical and Computer Engineering Purdue University West Lafayette IN USA Department of Materials Science and Engineering The Pennsylvania State University University Park PA USA

ISBN: (数字)9798350323108

ISBN: (纸本)9798350323115

The dielectric environment plays a significant role in the performance of transition metal dichalcogenide FETs. In a previous study, a low mobility of monolayer (ML) MoS2 was extracted when located on an ultrathin dielectric [1]. Here, we have performed a comparative study of ML MoS2 on a number of low-κ/high-κ dielectrics and found that the mobility does not depend on the choice of dielectric if an “air gap” between the MoS2 and the dielectric is accounted for. This implies that remote phonon scattering plays a small or no role for the transport in MoS2. Moreover, we observed that mobility is independent on carrier concentrations and limited by intrinsic phonon scattering for both low-κ/high-κ dielectrics.

关键词： Field effect transistors Air gaps Scattering Phonons Dielectrics Sulfur Transition metal dichalcogenides

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Short-Range Communication for Small Biomedical Implants using Magnetoelectric Effect

Short-Range Communication for Small Biomedical Implants usin...

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IEEE International Symposium on Circuits and Systems (ISCAS)

作者： Sujay Hosur Sumanta Kumar Karan Shashank Priya Mehdi Kiani School of Electrical Engineering and Computer Science The Pennsylvania State University University Park PA USA Department of Materials Science and Engineering The Pennsylvania State University University Park PA USA

This paper introduces a technique, called monotonic energy transmission (MET), for short-range wireless data transfer from small implantable devices with millimeter (mm) scale dimensions to an external unit using the magnetoelectric (ME) effect. In the proposed technique, while low-frequency magnetic field is used to power an implant which integrates a small ME transducer, data is transferred by driving the ME transducer with an initiation and a suppression sinusoid, which are 180° apart in phase. Transmitting both sinusoids improves the data rate and minimizes the inter-symbol interference (ISI). This technique was combined with pulse position modulation (PPM) to further increase the data rate. This paper describes the theory behind the proposed technique and demonstrates its operation through measurements using a $6.56\times 2.63\times 0.67 \ \text{mm}^{3}$ ME transducer fabricated with Metglas and PZT-5A as the magnetostrictive and piezoelectric layers, respectively. In measurements, 220 kbps data rate was achieved using a delay detection resolution of 1 ns with an ME transducer operating at 274 kHz.

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Measurement of Absorption Current of Polyester Coated Enameled Wires with Q(t) meter

Measurement of Absorption Current of Polyester Coated Enamel...

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2023 International Symposium on electrical Insulating materials, ISEIM 2023

作者： Watanabe, Akinao Fukuma, Masumi Sekiguchi, Yoitsu Advanced Electronic and Information Systems Course National Institute of Technology Matsue College Matsue Japan Department of Electrical Engineering and Computer Science National Institute of Technology Matsue College Matsue Japan Energy and Electronics Materials R&D Laboratories Sumitomo Electric Industries Osaka Japan

ISBN: (纸本)9784886864376

A Q(t) meter is used to measure electrical properties in insulating materials. Here, Q(t) is the integral value of circuit current with time t. It is possible to measure the Q(t) of the insulation material of a capacitor and a cable by using Q(t) meter. The current through an insulating material is divided into an instantaneous charging current, an absorption current and an equilibrium leakage current. It is considered that the absorption current is related to charge accumulation in the insulating materials. In this paper, an enameled wire (1.6 PEW) is used to prepare a cable sample, the Q(t) of the coated polyester (PEs) is measured, and extraction of absorption current components from measured Q(t) are reported. © 2023 The Institute of electrical Engineers of Japan.

关键词： Insulating materials

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