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Tunneling spectroscopy of c-axis epitaxial cuprate junctions

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arXiv 2020年

作者： Zhou, Panpan Chen, Liyang Sochnikov, Ilya Wu, Tsz Chun Foster, Matthew S. Bollinger, Anthony T. He, Xi Božović, Ivan Natelson, Douglas Department of Physics and Astronomy Rice University HoustonTX77005 United States Applied Physics Graduate Program Smalley-Curl Institute Rice University HoustonTX77005 United States Department of Physics University of Connecticut StorrsCT06269 United States Brookhaven National Laboratory UptonNY11973-5000 United States Department of Chemistry Yale University New HavenCT06520 United States Department of Electrical and Computer Engineering Rice University HoustonTX77005 United States Department of Materials Science and NanoEngineering Rice University HoustonTX77005 United States

Atomically precise epitaxial structures are unique systems for tunneling spectroscopy that minimize extrinsic effects of disorder. We present a systematic tunneling spectroscopy study, over a broad doping, temperature, and bias range, in epitaxial c-axis La2−xSrxCuO4/La2CuO4/La2−xSrxCuO4 heterostructures. The behavior of these superconductor/insulator/superconductor (SIS) devices is unusual. Down to 20 mK there is complete suppression of c-axis Josephson critical current with a barrier of only 2 nm of La2CuO4, and the zero-bias conductance remains at 20-30% of the normal-state conductance, implying a substantial population of in-gap states. Tunneling spectra show greatly suppressed coherence peaks. As the temperature is raised, the superconducting gap fills in rather than closing at Tc. For all doping levels, the spectra show an inelastic tunneling feature at ∼ 80 meV, suppressed as T exceeds Tc. These nominally simple epitaxial cuprate junctions deviate markedly from expectations based on the standard Bardeen-Cooper-Schrieffer (BCS) theory. Copyright © 2020, The Authors. All rights reserved.

关键词： Copper compounds

Skeletal Muscle Regeneration: Functional Skeletal Muscle Regeneration with Thermally Drawn Porous Fibers and Reprogrammed Muscle Progenitors for Volumetric Muscle Injury (Adv. Mater. 14/2021)

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Advanced materials 2021年第14期33卷

作者： Yoonhee Jin Dena Shahriari Eun Je Jeon Seongjun Park Yi Sun Choi Jonghyeok Back Hyungsuk Lee Polina Anikeeva Seung-Woo Cho Department of Biotechnology Yonsei University Seoul 03722 Republic of Korea Research Laboratory of Electronics Massachusetts Institute of Technology Cambridge MA 02139 USA McGovern Institute for Brain Research Cambridge MA 02139 USA Department of Biomaterials Science and Engineering Yonsei University Seoul 03722 Republic of Korea Department of Bio and Brain Engineering Korea Advanced Institute of Science and Technology (KAIST) Daejeon 34141 Republic of Korea KAIST Institute for Health Science and Technology Daejeon 34141 Republic of Korea School of Mechanical Engineering Yonsei University Seoul 03722 Republic of Korea Department of Materials Science and Engineering Massachusetts Institute of Technology Cambridge MA 02139 USA Department of Brain and Cognitive Sciences Massachusetts Institute of Technology Cambridge MA 02139 USA Center for Nanomedicine Institute for Basic Science (IBS) Seoul 03722 Republic of Korea Graduate Program of Nano Biomedical Engineering (NanoBME) Advanced Science Institute Yonsei University Seoul 03722 Republic of Korea

Influence of MIG/MAG Welding Process on Mechanical and Pitting Corrosion Behaviors on the Super-Duplex Stainless Steel SAF 2507 Welded Joints

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materials sciences and Applications 2018年第2期9卷 228-245页

作者： Bruno Leonardy S. Lopes Samuel F. Rodrigues Eden S. Silva Gedeon S. Reis Waldemir dos P. Martins Juvenilson Costa Damascena Valdemar S. Leal Graduate Program in Materials Engineering Federal Institute of Education Science and Technology of Maranh&atilde o—IFMA S&atilde o Luís MA Brazil Engineering Coordination Universidade UNICEUMA S&atilde o Luís MA Brazil

The main objective of this research is to better understand the correlation between the constituent phases presented in the super-duplex steel SAF 2507 when it is under welding process by arc shielding gas MIG-MAG (Metal Inert Gas-Metal Active Gas). Conventional short circuit transfer and derivative STT (Surface Tension Transfer) using the 2594 welding wire as a filler metal and the effects on welding power in hardness, toughness and pitting corrosion are considered here. The results showed that the welding energy (Ew) changed the α/γ-phase’s balance and occasionally formed σ-phase in ferrite grain boundaries which led to changes in hardness, toughness and pitting corrosion resistance in molten zone (MZ), heat activated zone (HAZ) and metal base regions (MB). Furthermore, the increased amount of γ-phase improved the pitting corrosion resistance index (PRENγ) mainly in the MZ. This is due to decrease of α-phase fraction and formation of coarser grains, for higher welding energy. The toughness in the MZ decreased with less formation of γ-phase, coalescence of ferritic grains and localized formation of σ-phase, raising the hardness in the HAZ when the welding energy was lower.

关键词： Super-Duplex Steels Welding Toughness Pitting Corrosion Microhardness

Tunable plasmonic ultrastrong coupling: Emulating dicke physics at room temperature

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arXiv 2021年

作者： Yahiaoui, Riad Chase, Zizwe A. Kyaw, Chan Tay, Fuyang Baydin, Andrey Noe, G. Timothy Song, Junyeob Kono, Junichiro Agrawal, Amit Bamba, Motoaki Searles, Thomas A. Department of Physics and Astronomy Howard University WashingtonDC20059 United States Department of Electrical and Computer Engineering Rice University HoustonTX70005 United States Applied Physics Graduate Program Smalley-Curl Institute Rice University HoustonTX77005 United States Smalley-Curl Institute Rice University HoustonTX77005 United States Physical Measurement Laboratory National Institute of Standards and Technology GaithersburgMD20899 United States Department of Physics and Astronomy Rice University HoustonTX77005 United States Department of Materials Science and NanoEngineering Rice University HoustonTX77005 United States Maryland NanoCenter University of Maryland College ParkMD20742 United States The Hakubi Center for Advanced Research Kyoto University Kyoto606-8502 Japan Department of Physics I Kyoto University Kyoto606-8502 Japan Department of Physics Massachusetts Institute of Technology CambridgeMA02139 United States

A system of N two-level atoms cooperatively interacting with a photonic field can be described as a single giant atom coupled to the field with interaction strength ∝ √N. This enhancement, known as Dicke cooperativity in quantum optics, has recently become an indispensable element in quantum information technology based on strong light-matter coupling. Here, we extend the coupling beyond the standard light-matter interaction paradigm, emulating Dicke cooperativity in a terahertz metasurface with N meta-atoms. Cooperative enhancement manifested in the form of matter-matter coupling, through the hybridization of localized surface plasmon resonance in individual meta-atoms and surface lattice resonance due to the periodic array of the meta-atoms. By varying the lattice constant of the array, we observe a clear anticrossing behavior, a signature of strong coupling. Furthermore, through engineering of the capacitive split-gap in the meta-atoms, the coupling rate was cooperatively enhanced into the ultrastrong coupling regime by a factor of √N. This room-temperature technology serves as a convenient quantum emulator of the dynamics of a qubit with a giant dipole moment coherently driven by a single bosonic field. Copyright © 2021, The Authors. All rights reserved.

关键词： Atoms

All-optical reconfigurable chiral meta-molecules

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arXiv 2019年

作者： Lin, Linhan Lepeshov, Sergey Krasnok, Alex Jiang, Taizhi Peng, Xiaolei Korgel, Brian A. Alu, Andrea Zheng, Yuebing Department of Mechanical Engineering University of Texas at Austin AustinTX78712 United States Materials Science & Engineering Program Texas Materials Institute University of Texas at Austin AustinTX78712 United States ITMO University St. Petersburg197101 Russia Department of Electrical and Computer Engineering University of Texas at Austin AustinTX78712 United States Mc Ketta Department of Chemical Engineering University of Texas at Austin AustinTX78712 United States Photonics Initiative Advanced Science Research Center City University of New York New YorkNY10031 United States Physics Program Graduate Center City University of New York NY10016 United States Department of Electrical Engineering City College of The City University New YorkNY10031 United States

Chirality is a ubiquitous phenomenon in the natural world. Many biomolecules without inversion symmetry such as amino acids and sugars are chiral molecules. Measuring and controlling molecular chirality at a high precision down to the atomic scale are highly desired in physics, chemistry, biology, and medicine, however, have remained challenging. Herein, we achieve all-optical reconfigurable chiral meta-molecules experimentally using metallic and dielectric colloidal particles as artificial atoms or building blocks to serve at least two purposes. One is that the on-demand meta-molecules with strongly enhanced optical chirality are well-suited as substrates for surface-enhanced chiroptical spectroscopy of chiral molecules and as active components in optofluidic and nanophotonic devices. The other is that the bottom-up-assembled colloidal meta-molecules provide microscopic models to better understand the origin of chirality in the actual atomic and molecular systems. Copyright © 2019, The Authors. All rights reserved.

关键词： Atoms

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

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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

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

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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

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

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

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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