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Terahertz faraday and kerr rotation spectroscopy of Bi1−xSbx films in high magnetic fields up to 30 Tesla

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arXiv 2019年

作者： Li, Xinwei Yoshioka, Katsumasa Xie, Ming Noe, G. Timothy Lee, Woojoo Peraca, Nicolas Marquez Gao, Weilu Hagiwara, Toshio Orjan, Handegard S. Nien, Li-Wei Nagao, Tadaaki Kitajima, Masahiro Nojiri, Hiroyuki Shih, Chih-Kang MacDonald, Allan H. Katayama, Ikufumi Takeda, Jun Fiete, Gregory A. Kono, Junichiro Department of Electrical and Computer Engineering Rice University HoustonTX77005 United States Department of Physics Graduate School of Engineering Yokohama National University Yokohama240-8501 Japan Department of Physics and Center for Complex Quantum Systems The University of Texas at Austin AustinTX78712 United States Department of Physics and Astronomy Rice University HoustonTX77005 United States National Institute for Materials Science Tsukuba Ibaraki305-0044 Japan Institute for Materials Research Tohoku University Sendai980-8577 Japan Department of Physics Northeastern University BostonMA02115 United States Department of Physics Massachusetts Institute of Technology CambridgeMA02139 United States Department of Material Science and NanoEngineering Rice University HoustonTX77005 United States

We report results of terahertz Faraday and Kerr rotation spectroscopy measurements on thin films of Bi1−xSbx, an alloy system that exhibits a semimetal-to-topological-insulator transition as the Sb composition x increases. By using a single-shot time-domain terahertz spectroscopy setup combined with a table-top pulsed mini-coil magnet, we conducted measurements in magnetic fields up to 30 T, observing distinctly different behaviors between semimetallic (x Copyright © 2019, The Authors. All rights reserved.

关键词： Optical conductivity

Amplification of surface plasmons in graphene-black phosphorus injection laser heterostructures

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arXiv 2019年

作者： Ryzhii, .V. Otsuji, .T. Ryzhii, .M. Dubinov, A.A. Aleshkin, V. Ya. Karasik, V.E. Shur, M.S. Research Institute of Electrical Communication Tohoku University Sendai980-8577 Japan Institute of Ultra High Frequency Semiconductor Electronics of Ras Moscow117105 Center for Photonics and Two-Dimensional Materials Moscow Institute of Physics Technology Dolgoprudny141700 Center for Photonics and Infrared Technology Bauman Moscow State Technical University Moscow111005 Department of Computer Science and Engineering University of Aizu Aizu-Wakamatsu965-8580 Japan Institute for Physics of Microstructures of Ras and Lobachevsky University of Nizhny Novgorod Nizhny Novgorod60395 Department of Electrical Computer and Systems Engineering Rensselaer Polytechnic Institute TroyNY12180 United States

We propose and evaluate the heterostructure based on the graphene-layer (GL) with the lateral electron injection from the side contacts and the hole vertical injection via the black phosphorus layer (PL) (p+PL-PL-GL heterostructure). Due to a relatively small energy of the holes injected from the PL into the GL (about 100 meV, smaller than the energy of optical phonons in the GL which is about 200 meV), the hole injection can effectively cool down the two-dimensional electron-hole plasma in the GL. This simplifies the realization of the interband population inversion and the achievement of the negative dynamic conductivity in the terahertz (THz) frequency range enabling the amplification of the surface plasmon modes. The later can lead to the plasmon lasing. The conversion of the plasmons into the output radiation can be used for a new types of the THz sources. Copyright © 2019, The Authors. All rights reserved.

关键词： Phosphorus

Polycrystalline ZrTe5 Parametrized as a Narrow-Band-Gap Semiconductor for Thermoelectric Performance

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Physical Review Applied 2018年第1期9卷 014025-014025页

作者： Samuel A. Miller Ian Witting Umut Aydemir Lintao Peng Alexander J. E. Rettie Prashun Gorai Duck Young Chung Mercouri G. Kanatzidis Matthew Grayson Vladan Stevanović Eric S. Toberer G. Jeffrey Snyder Department of Materials Science and Engineering Northwestern University Evanston Illinois 60208 USA Department of Chemistry Koç University Sariyer Istanbul 34450 Turkey Applied Physics Graduate Program Northwestern University Evanston Illinois 60208 USA Materials Science Division Argonne National Laboratory Argonne Illinois 60439 USA National Renewable Energy Laboratory Golden Colorado 80401 USA Department of Metallurgical and Materials Engineering Colorado School of Mines Golden Colorado 80401 USA Department of Chemistry Northwestern University Evanston Illinois 60208 USA Department of Electrical Engineering and Computer Science Northwestern University Evanston Illinois 60208 USA Department of Physics Colorado School of Mines Golden Colorado 80401 USA

The transition-metal pentatellurides HfTe5 and ZrTe5 have been studied for their exotic transport properties with much debate over the transport mechanism, band gap, and cause of the resistivity behavior, including a large low-temperature resistivity peak. Single crystals grown by the chemical-vapor-transport method have shown an n−p transition of the Seebeck coefficient at the same temperature as a peak in the resistivity. We show that behavior similar to that of single crystals can be observed in iodine-doped polycrystalline samples but that undoped polycrystalline samples exhibit drastically different properties: they are p type over the entire temperature range. Additionally, the thermal conductivity for polycrystalline samples is much lower, 1.5 Wm−1 K−1, than previously reported for single crystals. It is found that the polycrystalline ZrTe5 system can be modeled as a simple semiconductor with conduction and valence bands both contributing to transport, separated by a band gap of 20 meV. This model demonstrates to first order that a simple two-band model can explain the transition from n- to p-type behavior and the cause of the anomalous resistivity peak. Combined with the experimental data, the two-band model shows that carrier concentration variation is responsible for differences in behavior between samples. Using the two-band model, the thermoelectric performance at different doping levels is predicted, finding zT=0.2 and 0.1 for p and n type, respectively, at 300 K, and zT=0.23 and 0.32 for p and n type at 600 K. Given the reasonably high zT that is comparable in magnitude for both n and p type, a thermoelectric device with a single compound used for both legs is feasible.

关键词： Band gap Charge density waves Hall effect Semimetals Spin-orbit coupling Thermoelectric effects Chalcogenides Semiconductor compounds

Emerging materials for tailorable nanophotonic devices

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Emerging materials for tailorable nanophotonic devices

International Congress on Advanced Electromagnetic materials in Microwaves and Optics (METAmaterials)

作者： Z. Wang D. Shah K. Chaudhuri A. Catellani M. Alhabeb H. Reddy X. Meng S. I. Azzam N. Kinsey A. V. Kildishev Y. L. Kim V. M. Shalaev A. Calzolari Y. Gogotsi A. Boltasseva School of Electrical & Computer Engineering and Birck Nanotechnology Center Purdue University West Lafayette IN USA CNR-NANO Instituto Nanoscienze Modena IT Department of Materials Science and Engineering Drexel University Philadelphia PA USA Department of Electrical and Computer Engineering Virginia Commonwealth University Richmond VA USA Weldon School of Biomedical Engineering Purdue University West Lafayette IN USA

We report on two classes of emerging materials, ultra-thin TiN and MXenes, as a potential material platform for plasmonic metamaterials. Due to their increased sensitivity to structural and compositional parameters, b... 详细信息

关键词： Plasmons Tin Metamaterials Optical films Two dimensional displays Substrates

Improving positioning accuracy of the mobile laser scanning in GPS-denied environments: An experimental case study

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arXiv 2019年

作者： Liu, Wi Li, Zhixiong Sun, Shuaishuai Malekian, Reza Ma, Zhenjun Li, Weihua School of Mechanical and Electrical Engineering China University of Mining and Technology Xuzhou221116 China Jiangsu Collaborative Innovation Center of Intelligent Mining Equipment China University of Mining and Technology Xuzhou210008 China School of Engineering Ocean University of China Tsingdao266100 China School of Mechanical Materials Mechatronic and Biomedical Engineering University of Wollongong WollongongNSW2522 Australia New Industry Creation Hatchery Center Tohoku University Sendai980-8577 Japan Department of Computer Science and Media Technology Malmö University Malmö20506 Sweden

The positioning accuracy of the mobile laser scanning (MLS) system can reach the level of centimeter under the conditions where GPS works normally. However, in GPS-denied environments this accuracy can be reduced to the decimeter or even the meter level because the observation mode errors and the boresight alignment errors of MLS cannot be calibrated or corrected by the GPS signal. To bridge this research gap, this paper proposes a novel technique that appropriately incorporates the robust weight total least squares (RWTLS) and the full information maximum likelihood optimal estimation (FIMLOE) to improve the positioning accuracy of the MLS system under GPS-denied environment. First of all, the coordinate transformation relationship and the observation parameters vector of MLS system are established. Secondly, the RWTLS algorithm is used to correct the 3D point observation model;then the uncertainty propagation parameter vector and the boresight alignment errors between the laser scanner frame and the IMU frame are calibrated by FIMLOE. Lastly, experimental investigation in indoor scenarios was performed to evaluate the effectiveness of the proposed method. The experimental results demonstrate that the proposed method is able to significantly improve the positioning accuracy of an MLS system in GPS-denied environments. Copyright © 2019, The Authors. All rights reserved.

关键词： Global positioning system

Charge separation at mixed-dimensional single and multilayer MoS2/silicon nanowire heterojunctions

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arXiv 2018年

作者： Henning, Alex Sangwan, Vinod K. Bergeron, Hadallia Balla, Itamar Sun, Zhiyuan Hersam, Mark C. Lauhon, Lincoln J. Department of Materials Science and Engineering Northwestern University EvanstonIL60208 United States Department of Chemistry Northwestern University EvanstonIL60208 United States Department of Electrical Engineering and Computer Science Northwestern University EvanstonIL60208 United States

Layered two-dimensional (2-D) semiconductors can be combined with other low-dimensional semiconductors to form non-planar mixed-dimensional van der Waals (vdW) heterojunctions whose charge transport behavior is influenced by the heterojunction geometry, providing a new degree of freedom to engineer device functions. Towards that end, we investigated the photoresponse of Si nanowire/MoS2 heterojunction diodes with scanning photocurrent microscopy and time-resolved photocurrent measurements. Comparison of n-Si/MoS2 isotype heterojunctions with p-Si/MoS2 heterojunction diodes under varying biases shows that the depletion region in the p-n heterojunction promotes exciton dissociation and carrier collection. We measure an instrument limited response time of 1 s, which is 10 times faster than previously reported response times for planar Si/MoS2 devices, highlighting the advantages of the 1-D/2-D heterojunction. Finite element simulations of device models provide a detailed understanding of how the electrostatics affect charge transport in nanowire/vdW heterojunctions and inform the design of future vdW heterojunction photodetectors and transistors. Copyright © 2018, The Authors. All rights reserved.

关键词： Heterojunctions

Self-aligned van der waals heterojunction diodes and transistors

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arXiv 2018年

作者： Sangwan, Vinod K. Beck, Megan E. Henning, Alex Luo, Jiajia Bergeron, Hadallia Kang, Junmo Balla, Itamar Inbar, Hadass Lauhon, Lincoln J. Hersam, Mark C. Department of Materials Science and Engineering Northwestern University EvanstonIL60208 United States Department of Chemistry Northwestern University EvanstonIL60208 United States Department of Electrical Engineering and Computer Science Northwestern University EvanstonIL60208 United States

A general self-aligned fabrication scheme is reported here for a diverse class of electronic devices based on van der Waals materials and heterojunctions. In particular, self-alignment enables the fabrication of source-gated transistors in monolayer MoS2 with near-ideal current saturation characteristics and channel lengths down to 135 nm. Furthermore, self-alignment of van der Waals p-n heterojunction diodes achieves complete electrostatic control of both the p-type and n-type constituent semiconductors in a dual-gated geometry, resulting in gate-tunable mean and variance of anti-ambipolar Gaussian characteristics. Through finite-element device simulations, the operating principles of source-gated transistors and dual-gated anti-ambipolar devices are elucidated, thus providing design rules for additional devices that employ self-aligned geometries. Copyright © 2018, The Authors. All rights reserved.

关键词： Heterojunctions

Role of Integrating Diffusion Mr Image-Markers with Clinical-Biomarkers for Early Assessment of Renal Transplants 25

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Role of Integrating Diffusion Mr Image-Markers with Clinical...

25th IEEE International Conference on Image Processing, ICIP 2018

作者： Shehata, Mohammad Ghazal, Mohammed Beache, Garth Ei-Ghar, Mohamed Abou Dwyer, Amy Hajjdiab, Hassan Khalil, Ashraf Ei-Baz, Ayman Bioengineering Department University of Louisville LouisvilleKY United States Electrical and Computer Engineering Department Abu Dhabi University Abu Dhabi United Arab Emirates Radiology Department University of Louisville LouisvilleKY United States Radiolozy Department Urology and Nephrology Center Mansoura University Mansoura Egypt Kidney Disease Program University of Louisville LouisvilleKY United States Computer Science and Information Technology Department Abu Dhabi University Abu Dhabi United Arab Emirates

ISBN: (纸本)9781479970612

Recently, diffusion-weighted magnetic resonance imaging (DW-MRI) has been explored for non-invasive assessment of renal transplant functions. In this paper, a computer-aided diagnostic (CAD) system is developed to assess renal transplant functionality, which integrates both clinical and diffusion MRI -derived markers extracted from 4D DW-MRI (i.e. 3D + b-value). To extract the DW-MR image-markers, our framework performs multiple image processing steps, including kidney segmentation using a level-set approach and estimation of image-markers. To extract these image-markers, apparent diffusion coefficients (ADCs) are estimated from the segmented DW-MRIs and cumulative distribution functions (CDFs) of the ADCs are constructed at different b-values (i.e. gradient field strengths and duration). Finally, these markers (i.e. CDFs) are integrated with clinical biomarkers (e.g., creatinine clearance and serum plasma creatinine) to assess transplant status using stacked auto-encoders with non-negativity constraints based on deep learning classification approach. Our CAD system consists of two consecutive classification stages. The first stage classifier achieved a 96% accuracy, a 95% sensitivity, and a 100% specificity in distinguishing non-rejection (NR) from dysfunctional (DF) transplanted kidneys. Additionally, an overall accuracy of 94% has been obtained in the second stage in separating DF to acute rejection (AR) and different renal disease (DRD) transplants. Our preliminary results hold strong promise that the presented CAD system is of a high reliability to non-invasively diagnose renal transplant status. © 2018 IEEE.

关键词： Magnetic resonance imaging

Quantum Simulation for High Energy Physics

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arXiv 2022年

作者： Bauer, Christian W. Davoudi, Zohreh Balantekin, A. Baha Bhattacharya, Tanmoy Carena, Marcela de Jong, Wibe A. Draper, Patrick El-Khadra, Aida Gemelke, Nate Hanada, Masanori Kharzeev, Dmitri Lamm, Henry Li, Ying-Ying Liu, Junyu Lukin, Mikhail Meurice, Yannick Monroe, Christopher Nachman, Benjamin Pagano, Guido Preskill, John Rinaldi, Enrico Roggero, Alessandro Santiago, David I. Savage, Martin J. Siddiqi, Irfan Siopsis, George Van Zanten, David Wiebe, Nathan Yamauchi, Yukari Yeter-Aydeniz, Kübra Zorzetti, Silvia Physics Division Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Department of Physics Maryland Center for Fundamental Physics University of Maryland College ParkMD20742 United States Department of Physics University of Wisconsin MadisonWI53706 United States T-2 Los Alamos National Laboratory Los AlamosNM87545 United States Fermi National Accelerator Laboratory BataviaIL60510 United States Enrico Fermi Institute University of Chicago ChicagoIL60637 United States Kavli Institute for Cosmological Physics University of Chicago ChicagoIL60637 United States Department of Physics University of Chicago ChicagoIL60637 United States Department of Physics Illinois Center for the Advanced Study of the Universe and Illinois Quantum Information Science and Technology Center University of Illinois UrbanaIL61801 United States QuEra Computing Inc BostonMA02135 United States Department of Mathematics University of Surrey Guildford Surrey GU2 7XH United Kingdom Center for Nuclear Theory Department of Physics and Astronomy Stony Brook University NY11794-3800 United States Department of Physics Brookhaven National Laboratory UptonNY11973 United States Pritzker School of Molecular Engineering Chicago Quantum Exchange Kadanoff Center for Theoretical Physics University of Chicago IL60637 United States QBraid Co. Harper Court 5235 ChicagoIL60615 United States Department of Physics Harvard University CambridgeMA02138 United States Department of Physics and Astronomy University of Iowa Iowa CityIA52242 United States Duke Quantum Center Duke University DurhamNC27701 United States Department of Electrical and Computer Engineering Duke University DurhamNC27708 United States Department of Physics Duke University DurhamNC27708 United States IonQ Inc. College ParkMD20740 United States Physics and Astronomy Department Rice University HoustonTX77005 United States Institute for Quantum Information and Matter Californi

It is for the first time that quantum simulation for High Energy Physics (HEP) is studied in the U.S. decadal particle-physics community planning, and in fact until recently, this was not considered a mainstream topic in the community. This fact speaks of a remarkable rate of growth of this subfield over the past few years, stimulated by the impressive advancements in Quantum Information sciences (QIS) and associated technologies over the past decade, and the significant investment in this area by the government and private sectors in the U.S. and other countries. High-energy physicists have quickly identified problems of importance to our understanding of nature at the most fundamental level, from tiniest distances to cosmological extents, that are intractable with classical computers but may benefit from quantum advantage. They have initiated, and continue to carry out, a vigorous program in theory, algorithm, and hardware co-design for simulations of relevance to the HEP mission. This community whitepaper is an attempt to bring this exciting and yet challenging area of research to the spotlight, and to elaborate on what the promises, requirements, challenges, and potential solutions are over the next decade and beyond. © 2022, CC BY.

关键词： High energy physics