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Disorder-driven glasslike thermal conductivity in colusite Cu26V2Sn6S32 investigated by Mössbauer spectroscopy and inelastic neutron scattering

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Physical Review materials 2020年第2期4卷 025404-025404页

作者： Christophe Candolfi Gabin Guélou Cédric Bourgès Andrew R. Supka Rabih Al Rahal Al Orabi Marco Fornari Bernard Malaman Gérard Le Caër Pierric Lemoine Vincent Hardy Jean-Marc Zanotti Raju Chetty Michihiro Ohta Koichiro Suekuni Emmanuel Guilmeau Institut Jean Lamour UMR 7198 CNRS – Université de Lorraine 2 allée André Guinier-Campus ARTEM BP 50840 54011 Nancy Cedex France Laboratoire CRISMAT UMR 6508 CNRS ENSICAEN 6 Boulevard du Maréchal Juin 14050 Caen Cedex 04 France Department of Physics and Science of Advanced Materials Program Central Michigan University Mt. Pleasant Michigan 48859 United States Solvay Design and Development of Functional Materials Department AXEL’ ONE Collaborative Platform − Innovative Materials 87 Rue des Freres Perret − BP62 69192 Saint Fons Cedex France Institut de Physique de Rennes UMR UR1-CNRS 6251 Université de Rennes I Campus de Beaulieu 35042 Rennes Cedex France Université de Rennes CNRS ISCR – UMR 6226 F-35000 Rennes France Laboratoire Léon Brillouin CNRS-CEA (UMR 12) CNRS Université Paris-Saclay CEA Saclay 91191 Gif-sur-Yvette Cedex France Research Institute for Energy Conservation National Institute of Advanced Industrial Science and Technology (AIST) Tsukuba Ibaraki 305–8568 Japan Department of Applied Science for Electronics and Materials Interdisciplinary Graduate School of Engineering Sciences Kyushu University Kasuga Fukuoka 816–8580 Japan

The influence of structural disorder on the thermal transport in the colusite Cu26V2Sn6S32 has been investigated by means of low-temperature thermal conductivity and specific heat measurements (2–300 K), Sn119 Mössbauer spectroscopy and temperature-dependent powder inelastic neutron scattering (INS). Variations in the high-temperature synthesis conditions act as a key parameter for tuning the degree of disorder in colusite compounds. Intriguingly, we find that all synthesized samples are disordered, the degree of which varies with the synthesis conditions used. Mössbauer data clearly evidence that Sn atoms do not solely occupy the 6c site of the crystal lattice but are present on possibly both the Cu and V sites, leading to a random distribution of these three cations within the unit cell. Increasing the disorder in these materials tends to lead to a smearing out of the main features in the phonon density of states measured by INS. Although the evolution of the inelastic signal upon warming is well described by a quasiharmonic approximation, elastic properties calculations indicate large average Grüneisen parameters, consistent with those determined experimentally from thermodynamic data. Increasing the level of disorder results in a decreased average Grüneisen parameter suggesting that the lowered lattice thermal conductivity is not driven by enhanced anharmonicity. These results provide experimental evidence to support that the remarkable changeover in the lattice thermal conductivity from crystalline to glasslike is solely driven by enhanced disorder accompanied by local lattice distortions.

关键词： Thermal properties Polycrystalline materials Mössbauer spectroscopy Time-of-flight neutron spectroscopy

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Hybrid Opals: Transparent Hybrid Opals with Unexpected Strong Resonance-Enhanced Photothermal Energy Conversion (Adv. Mater. 2/2021)

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Advanced materials 2021年第2期33卷

作者： Yu Cang Jaejun Lee Zuyuan Wang Jiajun Yan Krzysztof Matyjaszewski Michael R. Bockstaller George Fytas School of Aerospace Engineering and Applied Mechanics Tongji University 100 Zhangwu Road Shanghai 200092 China Max Planck Institute for Polymer Research Ackermannweg 10 Mainz 55128 Germany Department of Materials Science and Engineering Carnegie Mellon University 5000 Forbes Avenue Pittsburgh PA 15213 USA Chemistry Department Carnegie Mellon University 4400 Fifth Ave. Pittsburgh PA 15213 USA

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Magnetic Control of Soft Chiral Phonons in PbTe

arXiv

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arXiv 2021年

作者： Baydin, Andrey Hernandez, Felix G.G. Rodriguez-Vega, Martin Okazaki, Anderson K. Tay, Fuyang Timothy Noe, G. Katayama, Ikufumi Takeda, Jun Nojiri, Hiroyuki Rappl, Paulo H.O. Abramof, Eduardo Fiete, Gregory A. Kono, Junichiro Department of Electrical and Computer Engineering Rice University HoustonTX77005 United States Smalley-Curl Institute Rice University HoustonTX77005 United States Instituto de Física Universidade de São Paulo SP São Paulo05508-090 Brazil Theoretical Division Los Alamos National Laboratory Los AlamosNM87545 United States Laboratório Associado de Sensores e Materiais Instituto Nacional de Pesquisas Espaciais SP São José dos Campos12201-970 Brazil Applied Physics Graduate Program Smalley-Curl Institute Rice University HoustonTX77005 United States Department of Physics Graduate School of Engineering Science Yokohama National University Yokohama240-8501 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 Physics and Astronomy Rice University HoustonTX77005 United States Department of Material Science and NanoEngineering Rice University HoustonTX77005 United States

PbTe crystals have a soft transverse optical phonon mode in the terahertz frequency range, which is known to efficiently decay into heat-carrying acoustic phonons, resulting in anomalously low thermal conductivity. Here, we studied this phonon via polarization-dependent terahertz spectroscopy. We observed softening of this mode with decreasing temperature, indicative of incipient ferroelectricity, which we explain through a model including strong anharmonicity with a quartic displacement term. In magnetic fields up to 25 T, the phonon mode splits into two modes with opposite handedness, exhibiting circular dichroism. Their frequencies display Zeeman splitting together with an overall diamagnetic shift with increasing magnetic field. Using a group-theoretical approach, we demonstrate that these observations are the result of magnetic field-induced morphic changes in the crystal symmetries through the Lorentz force exerted on the lattice ions. Thus, our study reveals a novel process of controlling phonon properties in a soft ionic lattice by a strong magnetic field. Copyright © 2021, The Authors. All rights reserved.

关键词： Magnetic fields

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Optimization-Based Approach for the Inverse Design of Ribbon-Shaped Three-Dimensional Structures Assembled Through Compressive Buckling

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Physical Review applied 2019年第5期11卷 054053-054053页

作者： Zheng Xu Zhichao Fan Haoran Fu Yuan Liu Yanyang Zi Yonggang Huang Yihui Zhang Applied Mechanics Laboratory Department of Engineering Mechanics Tsinghua University Beijing 100084 P.R. China Center for Flexible Electronics Technology Tsinghua University Beijing 100084 P.R. China State Key Laboratory for Manufacturing and Systems Engineering School of Mechanical Engineering Xi’an Jiaotong University Xi’an 710049 P.R. China Institute of Flexible Electronics Technology of Tsinghua Zhejiang 314006 P.R. China Departments of Civil and Environmental Engineering Mechanical Engineering and Materials Science and Engineering Center for Bio-Integrated Electronics Northwestern University Evanston Illinois 60208 USA

Mechanically driven assembly of three-dimensional (3D) mesostructures by compressive buckling represents an area of increasing attention, owing to the excellent compatibility with planar fabrication technologies and the broad applicability to a variety of material types (from semiconductors to metals and dielectrics) and length scales (from nanometers to centimeters). As a representative class of 3D geometries, the assembly of filamentary 3D ribbon configurations has been studied extensively, either to analyze the deformation features or to explore the applications in various functional devices. Previous studies mainly focused on the modeling of the “forward problem” that enables the prediction of the assembled 3D ribbon configuration for a prescribed 2D precursor. Development of an efficient method to solve the “inverse problem” that maps the target 3D geometry onto an unknown 2D precursor design remains a challenge. In the framework of adaptive-genetic-algorithm optimization, this paper proposes a systematic computational method to solve the inverse design problem of ribbon-shaped 3D structures assembled through compressive buckling. Based on a theoretical analysis on the inherent geometric relationship between the deformed and the initial ribbon configurations, we establish an optimization-based formulation of the inverse design problem to determine the initial geometries of 2D precursors, with the aid of finite-element analyses. Both the convergence and accuracy of the developed method are verified through a set of illustrative examples. Computational and experimental studies over approximately 20 ribbon structures, each with comparison between the target and assembled configurations, show the broad applicability of the inverse design method. Demonstrated capabilities to form 3D structures that resemble the sketches of real objects (e.g., peaked hat, butterfly, and frog) suggest promising utilities in the accurate design of functional devices.

关键词： Buckling Classical mechanics engineering Optimization problems Origami & Kirigami Devices Numerical approximation & analysis Topology

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Tunable plasmonic ultrastrong coupling: Emulating dicke physics at room temperature

arXiv

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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

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In-situ electric field control of THz non-reciprocal directional dichroism in the multiferroic Ba2CoGe2O7

arXiv

引用

arXiv 2021年

作者： Vít, J. Viirok, J. Peedu, L. Rõõm, T. Nagel, U. Kocsis, V. Tokunaga, Y. Taguchi, Y. Tokura, Y. Kézsmárki, I. Balla, P. Penc, K. Romhányi, J. Bordács, Sandor Department of Physics Budapest University of Technology and Economics Budapest1111 Hungary Institute of Physics Ascr Na Slovance 2 Prague 8182 21 Czech Republic Faculty of Nuclear Science and Physical Engineering Czech Technical University Břehová 7 Prague 1115 19 Czech Republic National Institute of Chemical Physics and Biophysics Akadeemia tee 23 Tallinn12618 Estonia Wako351-0198 Japan Department of Advanced Materials Science University of Tokyo Kashiwa277-8561 Japan Department of Applied Physics Tokyo College University of Tokyo Tokyo113-8656 Japan Experimental Physics v Center for Electronic Correlations and Magnetism University of Augsburg Augsburg86135 Germany Institute for Solid State Physics and Optics Wigner Research Centre or Physics PO Box. 49 BudapestH-1525 Hungary Department of Physics and Astronomy University of California Irvine 4129 Frederick Reines Hall IrvineCA United States Hungarian Academy of Sciences Premium Postdoctor Program Budapest1051 Hungary

Non-reciprocal directional dichroism, also called the optical-diode effect, is an appealing functional property inherent to the large class of non-centrosymmetric magnets. However, the in-situ electric control of this phenomenon is challenging as it requires a set of conditions to be fulfilled: Special symmetries of the magnetic ground state, spin-excitations with comparable magnetic- and electricdipole activity and switchable electric polarization. We demonstrate the isothermal electric switch between domains of Ba2CoGe2O7 possessing opposite magnetoelectric susceptibilities. Combining THz spectroscopy and multiboson spin-wave analysis, we show that unbalancing the population of antiferromagnetic domains generates the non-reciprocal light absorption of spin excitations. Copyright © 2021, The Authors. All rights reserved.

关键词： Electric fields

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Bridging particle deformability and collective response in soft solids

arXiv

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arXiv 2020年

作者： Treado, John D. Wang, Dong Boromand, Arman Murrell, Michael P. Shattuck, Mark D. O’Hern, Corey S. Department of Mechanical Engineering & Materials Science Yale University New HavenCT06520 United States Integrated Graduate Program in Physical and Engineering Biology Yale University New HavenCT06520 United States Department of Biomedical Engineering Yale University New HavenCT06520 United States Department of Physics Yale University New HavenCT06520 United States Systems Biology Institute Yale University West HavenCT06516 United States Benjamin Levich Institute and Physics Department The City College of New York New YorkNY10031 United States Department of Applied Physics Yale University New HavenCT06520 United States

Soft, amorphous solids such as tissues, foams, and emulsions are composed of deformable particles. However, the effect of single-particle deformability on the collective behavior of soft solids is still poorly understood. We perform numerical simulations of two-dimensional jammed packings of explicitly deformable particles to study the mechanical response of model soft solids. We find that jammed packings of deformable particles with excess shape degrees of freedom possess low-frequency quartic vibrational modes that stabilize the packings even though they possess fewer interparticle contacts than the nominal isostatic value. Adding intra-particle constraints can rigidify the particles, but these particles undergo a buckling transition and gain an effective shape degree of freedom when their preferred perimeter is above a threshold value. We find that the mechanical response of jammed packings of deformable particles with shape degrees of freedom differs significantly from that of jammed packings of rigid-shape particles, which emphasizes the importance of particle deformability in modelling soft solids. © 2020, CC BY.

关键词： Degrees of freedom (mechanics)

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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

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Fermi surface transformation at the pseudogap critical point of a cuprate superconductor

arXiv

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arXiv 2020年

作者： Fang, Yawen Grissonnanche, Gaël Legros, Anaëlle Verret, Simon Laliberté, Francis Collignon, Clément Ataei, Amirreza Dion, Maxime Zhou, Jianshi Graf, David Lawler, M.J. Goddard, Paul A. Taillefer, Louis Ramshaw, B.J. Laboratory of Atomic and Solid State Physics Cornell University IthacaNY United States Kavli Institute Cornell for Nanoscale Science IthacaNY United States Département de physique Institut quantique RQMP Université de Sherbrooke SherbrookeQC Canada SPEC CEA CNRS-UMR 3680 Université Paris-Saclay Gif-sur-Yvette France Materials Science and Engineering Program Department of Mechanical Engineering University of Texas at Austin AustinTX United States National High Magnetic Field Laboratory FL United States Department of Physics Applied Physics and Astronomy Binghamton University BinghamtonNY United States Department of Physics University of Warwick Coventry United Kingdom Canadian Institute for Advanced Research TorontoON Canada

The nature of the pseudogap phase remains a major puzzle in our understanding of cuprate high-temperature superconductivity. Whether or not this metallic phase is defined by any of the reported broken symmetries, the topology of its Fermi surface remains a fundamental open question. Here we use angle-dependent magnetoresistance (ADMR) to measure the Fermi surface of the cuprate La1.6−xNd0.4SrxCuO4. Outside of the pseudogap phase we can fit the ADMR data and extract a Fermi surface geometry that is in excellent agreement with angle-resolved photoemission data. Within the pseudogap regime the ADMR is qualitatively different, revealing a transformation of the Fermi surface. We can rule out changes in the quasiparticle lifetime as the sole cause of this transformation. We find that our data are most consistent with a pseudogap Fermi surface that consists of small, nodal hole pockets, thereby accounting for the drop in carrier density across the pseudogap transition found in several cuprates. Copyright © 2020, The Authors. All rights reserved.

关键词： Fermi surface

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DFT-FE – A massively parallel adaptive finite-element code for large-scale density functional theory calculations

arXiv

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arXiv 2019年

作者： Motamarri, Phani Das, Sambit Rudraraju, Shiva Ghosh, Krishnendu Davydov, Denis Gavini, Vikram Department of Mechanical Engineering University of Michigan Ann ArborMI48109 United States Department of Mechanical Engineering University of Wisconsin MadisonWI53706 United States Chair of Applied Mechanics Friedrich-Alexander-Universität Erlangen-Nürnberg Erlangen91058 Germany Department of Materials Science & Engineering University of Michigan Ann ArborMI48109 United States

We present an accurate, efficient and massively parallel finite-element code, DFT-FE, for large-scale ab-initio calculations (reaching ∼ 100, 000 electrons) using Kohn-Sham density functional theory (DFT). DFT-FE is based on a local real-space variational formulation of the Kohn-Sham DFT energy functional that is discretized using a higher-order adaptive spectral finite-element (FE) basis, and treats pseudopotential and all-electron calculations in the same framework, while accommodating non-periodic, semi-periodic and periodic boundary conditions. We discuss the main aspects of the code, which include, the various strategies of adaptive FE basis generation, and the different approaches employed in the numerical implementation of the solution of the discrete Kohn-Sham problem that are focused on significantly reducing the floating point operations, communication costs and latency. We demonstrate the accuracy of DFT-FE by comparing the energies, ionic forces and periodic cell stresses on a wide range of problems with popularly used DFT codes. Further, we demonstrate that DFT-FE significantly outperforms widely used plane-wave codes—both in CPU-times and wall-times, and on both non-periodic and periodic systems—at systems sizes beyond a few thousand electrons, with over 5 − 10 fold speedups in systems with more than 10,000 electrons. The benchmark studies also highlight the excellent parallel scalability of DFT-FE, with strong scaling demonstrated on up to 192,000 MPI tasks. Copyright © 2019, The Authors. All rights reserved.

关键词： Density functional theory

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