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Entanglement properties of disordered quantum spin chains with long-range antiferromagnetic interactions

Physical Review B 2020年第21期102卷 214201-214201页

作者： Y. Mohdeb J. Vahedi N. Moure A. Roshani Hyun-Yong Lee R. N. Bhatt Stefan Kettemann Stephan Haas Department of Physics and Earth Sciences Jacobs University Bremen Bremen 28759 Germany Technische Universität Braunschweig Institut für Mathematische Physik Mendelssohnstr. 3 38106 Braunschweig Germany Department of Physics Sari Branch Islamic Azad University Sari 48164-194 Iran Department of Physics and Astronomy University of Southern California Los Angeles California 90089-0484 USA Department of Applied Physics Graduate School Korea University Sejong 30019 Korea Division of Display and Semiconductor Physics Korea University Sejong 30019 Korea Interdisciplinary Program in EċICT-Culture-Sports Convergence Korea University Sejong 30019 Korea Department of Electrical Engineering Princeton University Princeton New Jersey 08544 USA School of Natural Sciences Institute for Advanced Study Princeton New Jersey 08540 USA Division of Advanced Materials Science Pohang University of Science and Technology (POSTECH) Pohang 790-784 Korea

Entanglement measures are useful tools in characterizing otherwise unknown quantum phases and indicating transitions between them. Here we examine the concurrence and entanglement entropy in quantum spin chains with random long-range couplings, spatially decaying with a power-law exponent α. Using the strong disorder renormalization group (SDRG) technique, we find by analytical solution of the master equation a strong disorder fixed point, characterized by a fixed point distribution of the couplings with a finite dynamical exponent, which describes the system consistently in the regime α>12. A numerical implementation of the SDRG method yields a power-law spatial decay of the average concurrence, which is also confirmed by exact numerical diagonalization. However, we find that the lowest-order SDRG approach is not sufficient to obtain the typical value of the concurrence. We therefore implement a correction scheme which allows us to obtain the leading-order corrections to the random singlet state. This approach yields a power-law spatial decay of the typical value of the concurrence, which we derive both by a numerical implementation of the corrections and by analytics. Next, using numerical SDRG, the entanglement entropy (EE) is found to be logarithmically enhanced for all α, corresponding to a critical behavior with an effective central charge c=ln(2), independent of α. This is confirmed by an analytical derivation. Using numerical exact diagonalization (ED), we confirm the logarithmic enhancement of the EE and a weak dependence on α. For a wide range of partition size l, the EE fits a critical behavior with a central charge close to c=1, which is the same as for the clean Haldane-Shastry model with a power-law-decaying interaction with α=2. Only for small l≪L, in a range which increases with the number of spins N, we find deviations which are rather consistent with the strong disorder fixed point central charge c=ln(2). Furthermore, we find using ED that the conc

关键词： Magnetism Quantum entanglement Disordered systems Doped semiconductors Density matrix methods Exact diagonalization Renormalization group Tensor network methods

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High-Throughput Computational Studies in Catalysis and materials Research, and their Impact on Rational Design

arXiv

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arXiv 2019年

作者： Afzal, Mohammad Atif Faiz Hachmann, Johannes Schrödinger Inc. PortlandOR97204 United States Department of Chemical and Biological Engineering University at Buffalo State University of New York BuffaloNY14260 United States Computational and Data-Enabled Science and Engineering Graduate Program University at Buffalo The State University of New York BuffaloNY14260 United States New York State Center of Excellence in Materials Informatics BuffaloNY14203 United States

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All-Electrical Determination of Crystal Orientation in Anisotropic Two-Dimensional materials

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Physical Review Letters 2018年第8期120卷 086801-086801页

作者： Lintao Peng Spencer A. Wells Christopher R. Ryder Mark C. Hersam Matthew Grayson Applied Physics Graduate Program Northwestern University Evanston Illinois 60208 USA Department of Materials Science and Engineering Northwestern University Evanston Illinois 60208 USA Department of Electrical Engineering and Computer Science Northwestern University Evanston Illinois 60208 USA Department of Chemistry Northwestern University Evanston Illinois 60208 USA

The crystal orientation of an exfoliated black phosphorous flake is determined by purely electrical means. A sequence of three resistance measurements on an arbitrarily shaped flake with five contacts determines the three independent components of the anisotropic in-plane resistivity tensor, thereby revealing the crystal axes. The resistivity anisotropy ratio decreases linearly with increasing temperature T and carrier density reaching a maximum ratio of 3.0 at low temperatures and densities, while mobility indicates impurity scattering at low T and acoustic phonon scattering at high T.

关键词： Crystal orientation Electrical conductivity Semiconductors Transport phenomena Multilayer thin films Phosphorene Transition metal dichalcogenides Resistivity measurements

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MoSi2N4single-layer: A novel two-dimensional material with outstanding mechanical, thermal, electronic, optical, and photocatalytic properties

arXiv

引用

arXiv 2020年

作者： Bafekry, A. Faraji, M. Hoat, Do M. Fadlallah, M.M. Shahrokhi, M. Shojaei, F. Gogova, D. Ghergherehchi, M. Department of Physics University of Guilan Rasht41335-1914 Iran Department of Physics University of Antwerp Groenenborgerlaan 171 AntwerpB-2020 Belgium Micro and Nanotechnology Graduate Program TOBB University of Economics and Technology Sogutozu Caddesi No 43 Sogutozu Ankara06560 Turkey Computational Laboratory for Advanced Materials and Structures Advanced Institute of Materials Science Ton Duc Thang University Ho Chi Minh City Viet Nam Department of Physics Faculty of Science Benha University Benha13518 Egypt University Lyon ENS de Lyon CNRS Universit Claude Bernard Lyon 1 Laboratoire de Chimie UMR 5182 LyonF-69342 France Department of Chemistry Faculty of Sciences Persian Gulf University Bushehr75169 Iran Department of Physics University of Oslo P.O. Box 1048 Blindern Oslo Norway College of Electronic and Electrical Engineering Sungkyun Kwan University Suwon Korea Republic of

Very recently, the two-dimensional (2D) form of MoSi2N4has been successfully fabricated [Hong et al., Sci. 369, 670 (2020)]. Motivated by theses recent experimental results, herein we investigate the structural, mechanical, thermal, electronic, optical and photocatalytic properties using hybrid density functional theory (HSE06-DFT). Phonon band dispersion calculations reveal the dynamical stability of MoSi2N4monolayer structure. Furthermore, the mechanical study confirms the stability of MoSi2N4monolayer. As compared to the corresponding value of graphene, we find the Young's modulus decreases by ∼ 30% while the Poisson's ratio increases by ∼ 30%. In addition, its work function is very similar to that of phosphorene and MoS2 monolayers. The electronic structure investigation shows the MoSi2N4monolayer is an indirect bandgap semiconductor. We have determined the bandgap using the HSE06 (GGA) is 2.35 (1.79) eV, which is an overestimated (underestimated) value of the experimental bandgap (1.99 eV). The thermoelectric study shows a good thermoelectric performance of the MoSi2N4monolayer with a figure of merit slightly larger than unity at high temperatures. The optical analysis using the RPA method constructed over HSE06 shows that the first absorption peak of the MoSi2N4monolayer for in-plane polarization is located in the visible range of spectrum, i.e. it is a promising candidate for advancing optoelectronic nanodevices. The photocatalytic study indicates the MoSi2N4monloayer can be a promising photocatalyst for water splitting as well as and CO2 reduction. In summary, the fascinating MoSi2N4monloayer is a promising 2D material in many applications due to its unique physical properties. Copyright © 2020, The Authors. All rights reserved.

关键词： Molybdenum compounds

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Exciton Localization of High-Quality ZnO/Mg_xZn_1-xO Multiple Quantum Wells on Si (111) with a Y₂O₃ Buffer Layer (vol 1, pg 3829, 2018)

引用

ACS APPLIED NANO materials 2018年第10期1卷 5958-5958页

作者： Liu, Wei-Rein Huang, Wei-Lun Wu, Yung-Chi Lai, Liang-Hsun Hsu, Chia-Hung Hsieh, Wen-Feng Chiang, Tsung-Hung Wan, H. W. Hong, M. Kao, J. National Synchrotron Radiation Research Center Hsinchu 30076 Taiwan Program for Science and Technology of Accelerator Light Source National Chiao Tung University Hsinchu 30010 Taiwan Department of Photonics College of Electrical and Computer Engineering National Chiao Tung University Hsinchu 30010 Taiwan Department of Photonics College of Electrical and Computer Engineering National Chiao Tung University Hsinchu 30010 Taiwan Department of Materials Science & Engineering National Tsing Hua University Hsinchu 30013 Taiwan Graduate Institute of Applied Physics and Department of Physics National Taiwan University Taipei 10617 Taiwan Department of Physics National Tsing Hua University Hsinchu 30013 Taiwan

We report the structural and optical properties of ten-period ZnO/MgxZn1–xO multiple quantum wells (MQWs) prepared on the most widely used semiconductor material, Si. The introduction of a nanometer thick high-k Y2O3transition layer between Si (111) substrate and a ZnO buffer layer significantly improves the structural perfection of the MQWs grown on top of it. The high structural quality of the ZnO/MgxZn1–xO MQWs is evidenced by the appearance of pronounced high order satellite peaks in X-ray crystal truncation rods; high resolution cross-sectional transmission electron microscopy images also confirmed the regularly arranged well and barrier layers. When the well width is less than ∼2.7 nm, the quantum-confined Stark effect in MQWs can be negligible. Not only the increasing exciton-binding energy but also reducing exciton–phonon coupling determined in temperature-dependent photoluminescence spectra indicate quantum-size effect. Our results demonstrate that ZnO/MgxZn1–xO MQWs integrated on Si have great potential in UV optoelectronic device applications.

关键词： Excitons Phonons Oxides Binding energy Layers

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Loss Allocation in AC OPF-Based Financial Transmission Rights Auction Models

Loss Allocation in AC OPF-Based Financial Transmission Right...

引用

North American Power Symposium (NAPS)

作者： Alburidy, Abdullah Fan, Lingling Taiwan International Graduate Program Academia Sinica and National Taiwan University Taiwan Department of Materials Science and Engineering National Chung Hsing University Taichung Taiwan

ISBN: (纸本)9781538626993

This paper presents two models of AC optimal power flow based Financial Transmission Rights (FTRs) allocation auction. Both models were compared with the conventional DC optimal power flow (DC-OPF) based model. Considering an FTR between two nodes as a real power injection at the source node and a power withdrawal at the sink node;the first model assumes that the net power due to FTRs equals zero. FTRs do not consider loss and the slack node is compensating for the total system losses. In the second model, it is suggested that each FTR's source node is taking care of a portion of the system loss by introducing a power injection. The portion of loss compensation is proportional to each FTR allocated amount, i.e., if one FTR is to use the grid more, then it should compensate more for the loss. To show the validity of all models and the advantages of the new suggested model, numerical examples of a 3-bus system and the IEEE 14-bus system are presented. All results are compared and explained.

关键词： Financial Transmission Rights FTR Allocation auction considering loss DCOPF ACOPF MATLAB Optimization Toolbox fmincon

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Nanostethoscopy: Atomic force microscopy probe contact force versus measured amplitude of cardiomyocytic contractions

引用

Journal of Bionanoscience 2017年第4期11卷 319-322页

作者： Vyas, Varun Nagarajan, Neerajha Zorlutuna, Pinar Huey, Bryan D. Institute of Materials Science University of Connecticut StorrsCT06269 United States Department of Aerospace and Mechanical Engineering Bioengineering Graduate Program University of Notre Dame Notre DameIN46556 United States

Cardiomyocytes are one of the most active cells in the human body. Understanding their mechanical contractions via nanostethoscopy has given us better insight into the subtleties of contractions. There is extensive data available on the temporal behavior of contraction in a cardiomyocytes but little is known about how contact force of the AFM probe influences the measurement force of contractions i.e., mean beat force. This investigation suggests that in order to accurately measure mean beat force nanostethoscopy data should be analyzed from the lowest to the highest contact force. In this study optimal contact force was varied from 10 nN to 500 nN and it was observed that the maximum contraction i.e., mean beat force was highest at contact force of 250 nN. © 2017 American Scientific Publishers.

关键词： Atomic force microscopy

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Full-color complex-amplitude vectorial holograms based on multi-freedom metasurfaces

arXiv

引用

arXiv 2019年

作者： Deng, Zi-Lan Jin, Mingke Ye, Xuan Wang, Shuai Shi, Tan Deng, Junhong Mao, Ningbin Cao, Yaoyu Guan, Bai-Ou Alù, Andrea Li, Guixin Li, Xiangping Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications Institute of Photonics Technology Jinan University Guangzhou510632 Department of Materials Science and Engineering Southern University of Science and Technology Shenzhen518055 China Shenzhen Institute for Quantum Science and Engineering Southern University of Science and Technology Shenzhen518055 China Photonics Initiative Advanced Science Research Center City University of New York 85 St. Nicholas Terrace New YorkNY10031 United States Physics Program Graduate Center City University of New York 365 Fifth Avenue New YorkNY10016 United States Department of Electrical Engineering City College of New York New YorkNY10031 United States

Phase, polarization, amplitude and frequency represent the basic dimensions of light, playing crucial roles for both fundamental light-mater interactions and all major optical applications. Metasurface emerges as a compact platform to manipulate these knobs, but previous metasurfaces have limited flexibility to simultaneous control them. Here, we introduce a multi-freedom metasurface that can simultaneously and independently modulate phase, polarization and amplitude in an analytical form, and further realize frequency multiplexing by a k-space engineering technique. The multi-freedom metasurface seamlessly combine geometric Pancharatnam-Berry phase and detour phase, both of which are frequency-independent. As a result, it allows complex-amplitude vectorial hologram at various frequencies based on the same design strategy, without sophisticated nanostructure searching of massive size parameters. Based on this principle, we experimentally demonstrate full-color complex-amplitude vectorial meta-holograms in the visible with a metal-insulator metal architecture, unlocking the long-sought full potential of advanced light field manipulation through ultrathin metasurfaces. Copyright © 2019, The Authors. All rights reserved.

关键词： Polarization

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LZS/Al2O3 glass-ceramic composites sintered by fast firing

LZS/Al2O3 glass-ceramic composites sintered by fast firing

引用

作者： Arcaro, Sabrina Nieto, Maria Isabel Moreno, Rodrigo Salvador, Maria Dolores Borrell, Amparo Moreno, Berta Chinarro, Eva De Oliveira, Antonio Pedro Novaes Laboratory of Glass-Ceramic Materials VITROCER Federal University of Santa Catarina - UFSC Florianópolis SC88040-900 Brazil Graduate Program in Materials Science and Engineering - PGMAT Federal University of Santa Catarina - UFSC Florianópolis SC88040-900 Brazil Institute of Ceramics and Glass - CSIC Madrid Spain Institute of Materials Technology Polytechnic University of Valencia Spain

In this work, nanometric Al2O3 (1-5 vol.%) particles (13 nm, 100 m2/g) were added to a 19.58Li2O•11.10ZrO2•69.32SiO2 (mol%) (3.5 µm, 2.5 m2/g) parent glass-ceramic matrix to prepare composites with the purpose of studying the influence of Al2O3 on their structure, microstructure, mechanical, thermal and electrical properties when sintered by fast firing. The parent glass-ceramic was prepared by melting and fast cooling (in water) to obtain a glass frit. The resulting glass frit was milled according to a two-step procedure consisting on a dry milling stage followed by a long wet milling step down. Each composition was wet homogenized and then dried at 110 ºC for 48 h for disaggregation. The obtained powders were uniaxially pressed (100 MPa) and compacts sintered by fast firing (175 ºC/min) between 800 and 900 ºC for 30 min. The composites, with relative densities ranging from 89% to 93%, showed zircon and β-spodumene as main crystalline phases. The hardness and Young's modulus varied from 4.5 to 6.5 GPa, and from 65 to 102 GPa, respectively. The formation of β-spodumene in the obtained composites leads to reduce the CTEs, whose values ranged from 13 to 7 x 10-6 ºC-1 © 2017 Universidade Federal de Sao Carlos. All rights reserved.

关键词： Sintering

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Resolving spin, valley, and moiré quasi-angular momentum of interlayer excitons in WSe2/WS2 heterostructures

arXiv

引用

arXiv 2019年

作者： Jin, Chenhao Regan, Emma C. Wang, Danqing Iqbal Bakti Utama, M. Yang, Chan-Shan Cain, Jeffrey Qin, Ying Shen, Yuxia Zheng, Zhiren Watanabe, Kenji Taniguchi, Takashi Tongay, Sefaattin Zettl, Alex Wang, Feng Department of Physics University of California at Berkeley BerkeleyCA94720 United States Graduate Group in Applied Science and Technology University of California at Berkeley BerkeleyCA94720 United States Department of Materials Science and Engineering University of California at Berkeley BerkeleyCA94720 United States Institute of Electro-Optical Science and Technology Undergraduate Program of Electro-Optical Engineering National Taiwan Normal University Taipei11677 Taiwan Material Science Division Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Kavli Energy NanoSciences Institute University of California Berkeley Lawrence Berkeley National Laboratory BerkeleyCA94720 United States School for Engineering of Matter Transport and Energy Arizona State University TempeAZ85287 United States National Institute for Materials Science 1-1 Namiki Tsukuba305-0044 Japan

Moiré superlattices provide a powerful way to engineer properties of electrons and excitons in two-dimensional van der Waals heterostructures1-11. The moiré effect can be especially strong for interlayer excitons, where electrons and holes reside in different layers and can be addressed separately. In particular, it was recently proposed that the moiré superlattice potential not only localizes interlayer exciton states at different superlattice positions, but also hosts an emerging moiré quasi-angular momentum (QAM) that periodically switches the optical selection rules for interlayer excitons at different moiré sites12,13. Here we report the observation of multiple interlayer exciton states coexisting in a WSe2/WS2 moiré superlattice and unambiguously determine their spin, valley, and moiré QAM through novel resonant optical pump-probe spectroscopy and photoluminescence excitation spectroscopy. We demonstrate that interlayer excitons localized at different moiré sites can exhibit opposite optical selection rules due to the spatially-varying moiré QAM. Our observation reveals new opportunities to engineer interlayer exciton states and valley physics with moiré superlattices for optoelectronic and valleytronic applications. Copyright © 2019, The Authors. All rights reserved.

关键词： Angular momentum

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