1
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Torun G, Kishi T, Pugliese D, Milanese D, Bellouard Y. Formation Mechanism of Elemental Te Produced in Tellurite Glass Systems by Femtosecond Laser Irradiation. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2210446. [PMID: 36749876 DOI: 10.1002/adma.202210446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 12/23/2022] [Indexed: 05/19/2023]
Abstract
The formation of elemental trigonal tellurium (t-Te) on tellurite glass surfaces exposed to femtosecond laser pulses is discussed. Specifically, the underlying elemental crystallization phenomenon is investigated by altering laser parameters in common tellurite glass compositions under various ambient conditions. Elemental crystallization of t-Te by a single femtosecond laser pulse is unveiled by high-resolution imaging and analysis. The thermal diffusion model reveals the absence of lattice melting upon a single laser pulse, highlighting the complexity of the phase transformation. The typical cross-section displays three different crystal configurations over its depth, in which the overall thickness increases with each subsequent pulse. The effect of various controlled atmospheres shows the suppressing nature of the elemental crystallization, whereas the substrate temperature shows no significant impact on the nucleation of t-Te nanocrystals. This research gives new insight into the elemental crystallization of glass upon femtosecond laser irradiation and shows the potential to fabricate functional transparent electronic micro/nanodevices.
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Affiliation(s)
- Gözden Torun
- Galatea Laboratory, STI/IEM, Ecole Polytechnique Fédérale de Lausanne (EPFL), 2002, Neuchâtel, Switzerland
| | - Tetsuo Kishi
- Department of Materials Science and Engineering, Tokyo Institute of Technology, Tokyo, 152-8552, Japan
| | - Diego Pugliese
- Department of Electronics and Telecommunications, Polytechnic University of Turin, 10129, Turin, Italy
- Department of Applied Science and Technology and INSTM RU, Polytechnic University of Turin, 10129, Turin, Italy
| | - Daniel Milanese
- Department of Engineering and Architecture and INSTM RU, University of Parma, 43124, Parma, Italy
| | - Yves Bellouard
- Galatea Laboratory, STI/IEM, Ecole Polytechnique Fédérale de Lausanne (EPFL), 2002, Neuchâtel, Switzerland
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2
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Xi Y, Jing X, Xu Z, Liu N, Liu Y, Lin ML, Yang M, Sun Y, Zhuang J, Xu X, Hao W, Li Y, Li X, Wei X, Tan PH, Li Q, Liu B, Dou SX, Du Y. Superconductivity in Layered van der Waals Hydrogenated Germanene at High Pressure. J Am Chem Soc 2022; 144:18887-18895. [PMID: 36194558 DOI: 10.1021/jacs.2c05683] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The emergence of superconductivity in two-dimensional (2D) materials has attracted tremendous research efforts because the origins and mechanisms behind the unexpected and fascinating superconducting phenomena remain unclear. In particular, the superconductivity can survive in 2D systems even with weakened disorder and broken spatial inversion symmetry. Here, structural and superconducting transitions of 2D van der Waals (vdW) hydrogenated germanene (GeH) are observed under compression and decompression processes. GeH possesses a superconducting transition with a critical temperature (Tc) of 5.41 K at 8.39 GPa. A crystalline to amorphous transition occurs at 16.80 GPa, while superconductivity remains. An abnormal increase of Tc up to 6.11 K was observed during the decompression process, while the GeH remained in the 2D amorphous phase. A combination study of in situ high-pressure synchrotron X-ray diffraction, in situ high-pressure Raman spectroscopy, transition electron microscopy, and density functional theory simulations suggests that the superconductivity in 2D vdW GeH is attributed to the increased density of states at the Fermi level as well as the enhanced electron-phonon coupling effect under high pressure even in the form of an amorphous phase. The unique pressure-induced phase transition of GeH from 2D crystalline to 2D amorphous metal hydride provides a promising platform to study the mechanisms of amorphous hydride superconductivity.
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Affiliation(s)
- Yilian Xi
- School of Physics, Beihang University, Beijing100191, China.,BUAA-UOW Joint Research Centre, Institute for Superconducting and Electronic Materials (ISEM), Australian Institute for Innovative Materials (AIIM), University of Wollongong, Wollongong, New South Wales2500, Australia.,Centre of Quantum and Matter Sciences, International Research Institute for Multidisciplinary Science, Beihang University, Beijing100191, China
| | - Xiaoling Jing
- State Key Laboratory of Superhard Materials, Jilin University, Changchun130012, China
| | - Zhongfei Xu
- School of Physics, Beihang University, Beijing100191, China.,BUAA-UOW Joint Research Centre, Institute for Superconducting and Electronic Materials (ISEM), Australian Institute for Innovative Materials (AIIM), University of Wollongong, Wollongong, New South Wales2500, Australia.,College of Environmental Science and Engineering, North China Electric Power University, Beijing102206, China
| | - Nana Liu
- School of Physics, Beihang University, Beijing100191, China.,BUAA-UOW Joint Research Centre, Institute for Superconducting and Electronic Materials (ISEM), Australian Institute for Innovative Materials (AIIM), University of Wollongong, Wollongong, New South Wales2500, Australia
| | - Yani Liu
- School of Physics, Beihang University, Beijing100191, China.,BUAA-UOW Joint Research Centre, Institute for Superconducting and Electronic Materials (ISEM), Australian Institute for Innovative Materials (AIIM), University of Wollongong, Wollongong, New South Wales2500, Australia
| | - Miao-Ling Lin
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing100083, China
| | - Ming Yang
- School of Physics, Beihang University, Beijing100191, China
| | - Ying Sun
- School of Physics, Beihang University, Beijing100191, China
| | - Jincheng Zhuang
- School of Physics, Beihang University, Beijing100191, China.,BUAA-UOW Joint Research Centre, Institute for Superconducting and Electronic Materials (ISEM), Australian Institute for Innovative Materials (AIIM), University of Wollongong, Wollongong, New South Wales2500, Australia
| | - Xun Xu
- School of Physics, Beihang University, Beijing100191, China.,BUAA-UOW Joint Research Centre, Institute for Superconducting and Electronic Materials (ISEM), Australian Institute for Innovative Materials (AIIM), University of Wollongong, Wollongong, New South Wales2500, Australia
| | - Weichang Hao
- School of Physics, Beihang University, Beijing100191, China.,BUAA-UOW Joint Research Centre, Institute for Superconducting and Electronic Materials (ISEM), Australian Institute for Innovative Materials (AIIM), University of Wollongong, Wollongong, New South Wales2500, Australia.,Centre of Quantum and Matter Sciences, International Research Institute for Multidisciplinary Science, Beihang University, Beijing100191, China
| | - Yanchun Li
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing100049, China
| | - Xiaodong Li
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing100049, China
| | - Xiangjun Wei
- Shanghai Synchrotron Radiation Facility (SSRF), Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai201204, China
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing100083, China
| | - Quanjun Li
- State Key Laboratory of Superhard Materials, Jilin University, Changchun130012, China
| | - Bingbing Liu
- State Key Laboratory of Superhard Materials, Jilin University, Changchun130012, China
| | - Shi Xue Dou
- School of Physics, Beihang University, Beijing100191, China.,BUAA-UOW Joint Research Centre, Institute for Superconducting and Electronic Materials (ISEM), Australian Institute for Innovative Materials (AIIM), University of Wollongong, Wollongong, New South Wales2500, Australia.,Centre of Quantum and Matter Sciences, International Research Institute for Multidisciplinary Science, Beihang University, Beijing100191, China
| | - Yi Du
- School of Physics, Beihang University, Beijing100191, China.,BUAA-UOW Joint Research Centre, Institute for Superconducting and Electronic Materials (ISEM), Australian Institute for Innovative Materials (AIIM), University of Wollongong, Wollongong, New South Wales2500, Australia.,Centre of Quantum and Matter Sciences, International Research Institute for Multidisciplinary Science, Beihang University, Beijing100191, China
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3
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High-temperature superconductivity on the verge of a structural instability in lanthanum superhydride. Nat Commun 2021; 12:6863. [PMID: 34824193 PMCID: PMC8617267 DOI: 10.1038/s41467-021-26706-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 10/14/2021] [Indexed: 11/28/2022] Open
Abstract
The possibility of high, room-temperature superconductivity was predicted for metallic hydrogen in the 1960s. However, metallization and superconductivity of hydrogen are yet to be unambiguously demonstrated and may require pressures as high as 5 million atmospheres. Rare earth based “superhydrides”, such as LaH10, can be considered as a close approximation of metallic hydrogen even though they form at moderately lower pressures. In superhydrides the predominance of H-H metallic bonds and high superconducting transition temperatures bear the hallmarks of metallic hydrogen. Still, experimental studies revealing the key factors controlling their superconductivity are scarce. Here, we report the pressure and magnetic field dependence of the superconducting order observed in LaH10. We determine that the high-symmetry high-temperature superconducting Fm-3m phase of LaH10 can be stabilized at substantially lower pressures than previously thought. We find a remarkable correlation between superconductivity and a structural instability indicating that lattice vibrations, responsible for the monoclinic structural distortions in LaH10, strongly affect the superconducting coupling. The experimental studies to understand the superconductivity of superhydrides remain scarce. Here, the authors report pressure and magnetic field dependence of superconductivity in LaH10, and indicate lattice vibrations strongly affect superconducting coupling.
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4
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Marzari N, Ferretti A, Wolverton C. Electronic-structure methods for materials design. NATURE MATERIALS 2021; 20:736-749. [PMID: 34045704 DOI: 10.1038/s41563-021-01013-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 04/19/2021] [Indexed: 05/24/2023]
Abstract
The accuracy and efficiency of electronic-structure methods to understand, predict and design the properties of materials has driven a new paradigm in research. Simulations can greatly accelerate the identification, characterization and optimization of materials, with this acceleration driven by continuous progress in theory, algorithms and hardware, and by adaptation of concepts and tools from computer science. Nevertheless, the capability to identify and characterize materials relies on the predictive accuracy of the underlying physical descriptions, and on the ability to capture the complexity of realistic systems. We provide here an overview of electronic-structure methods, of their application to the prediction of materials properties, and of the different strategies employed towards the broader goals of materials design and discovery.
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Affiliation(s)
- Nicola Marzari
- Theory and Simulation of Materials (THEOS), and National Centre for Computational Design and Discovery of Novel Materials (MARVEL), École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
| | | | - Chris Wolverton
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, USA
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5
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Zhao C, Cai X, Liu L, Liu C, Zeng Z, Niu C, Xia C, Jia Y. Structural, Topological, and Superconducting Properties of Two‐Dimensional Tellurium Allotropes from Ab Initio Predictions. ADVANCED THEORY AND SIMULATIONS 2021. [DOI: 10.1002/adts.202000265] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Chunxiang Zhao
- International Laboratory for Quantum Functional Materials of Henan and School of Physics and Microelectronics Zhengzhou University Zhengzhou 450001 China
| | - Xiaolin Cai
- School of Physics and Electronic Information Engineering Henan Polytechnic University Jiaozuo 454000 China
| | - Liangliang Liu
- Key Laboratory for Special Functional Materials of Ministry of Education and School of Material Science and Engineering Henan University Kaifeng 475004 China
| | - Chengyan Liu
- Key Laboratory for Special Functional Materials of Ministry of Education and School of Material Science and Engineering Henan University Kaifeng 475004 China
| | - Zaiping Zeng
- Key Laboratory for Special Functional Materials of Ministry of Education and School of Material Science and Engineering Henan University Kaifeng 475004 China
| | - Chunyao Niu
- International Laboratory for Quantum Functional Materials of Henan and School of Physics and Microelectronics Zhengzhou University Zhengzhou 450001 China
| | - Congxin Xia
- College of Physics and Materials Science Henan Normal University Xinxiang 453007 China
| | - Yu Jia
- International Laboratory for Quantum Functional Materials of Henan and School of Physics and Microelectronics Zhengzhou University Zhengzhou 450001 China
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6
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Sjakste J, Tanimura K, Barbarino G, Perfetti L, Vast N. Hot electron relaxation dynamics in semiconductors: assessing the strength of the electron-phonon coupling from the theoretical and experimental viewpoints. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:353001. [PMID: 30084390 DOI: 10.1088/1361-648x/aad487] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The rapid development of the computational methods based on density functional theory, on the one hand, and of time-, energy-, and momentum-resolved spectroscopy, on the other hand, allows today an unprecedently detailed insight into the processes governing hot-electron relaxation dynamics, and, in particular, into the role of the electron-phonon coupling. Instead of focusing on the development of a particular method, theoretical or experimental, this review aims to treat the progress in the understanding of the electron-phonon coupling which can be gained from both, on the basis of recently obtained results. We start by defining several regimes of hot electron relaxation via electron-phonon coupling, with respect to the electron excitation energy. We distinguish between energy and momentum relaxation of hot electrons, and summarize, for several semiconductors of the IV and III-V groups, the orders of magnitude of different relaxation times in different regimes, on the basis of known experimental and numerical data. Momentum relaxation times of hot electrons become very short around 1 eV above the bottom of the conduction band, and such ultrafast relaxation mechanisms are measurable only in the most recent pump-probe experiments. Then, we give an overview of the recent progress in the experimental techniques allowing to obtain detailed information on the hot-electron relaxation dynamics, with the main focus on time-, energy-, and momentum-resolved photoemission experiments. The particularities of the experimental approach developed by one of us, which allows to capture time-, energy-, and momentum-resolved hot-electron distributions, as well as to measure momentum relaxation times of the order of 10 fs, are discussed. We further discuss the main advances in the calculation of the electron-phonon scattering times from first principles over the past ten years, in semiconducting materials. Ab initio techniques and efficient interpolation methods provide the possibility to calculate electron-phonon scattering times with high precision at reasonable numerical cost. We highlight the methods of analysis of the obtained numerical results, which allow to give insight into the details of the electron-phonon scattering mechanisms. Finally, we discuss the concept of hot electron ensemble which has been proposed recently to describe the hot-electron relaxation dynamics in GaAs, the applicability of this concept to other materials, and its limitations. We also mention some open problems.
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Affiliation(s)
- J Sjakste
- Laboratoire des Solides Irradiés, Ecole Polytechnique, CEA-DRF-IRAMIS, CNRS UMR 7642, 91120 Palaiseau, France
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7
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Liu Y, Hu S, Caputo R, Sun K, Li Y, Zhao G, Ren W. Allotropes of tellurium from first-principles crystal structure prediction calculations under pressure. RSC Adv 2018; 8:39650-39656. [PMID: 35558054 PMCID: PMC9091324 DOI: 10.1039/c8ra07843b] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 11/19/2018] [Indexed: 11/21/2022] Open
Abstract
We investigated the allotropes of tellurium under hydrostatic pressure based on density functional theory calculations and crystal structure prediction methodology. Our calculated enthalpy-pressure and energy-volume curves unveil the transition sequence from the trigonal semiconducting phase, represented by the space group P3121 in the range of 0–6 GPa, to the body centered cubic structure, space group Im3̄m, stable at 28 GPa. In between, the calculations suggest a monoclinic structure, represented by the space group C2/m and stable at 6 GPa, and the β-Po type structure, space group R3̄m, stable at 10 GPa. The face-centered structure is found at pressure as high as 200 GPa. As the pressure is increased, the transition from the semiconducting phase to metallic phases is observed. Through first-principles simulations, we suggest the phase stability of the allotropic transition sequence of tellurium from the trigonal structure up to the cubic structure.![]()
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Affiliation(s)
- Yuan Liu
- Materials Genome Institute
- International Centre for Quantum and Molecular Structures, and Department of Physics
- Shanghai University
- Shanghai 200444
- China
| | - Shunbo Hu
- Materials Genome Institute
- International Centre for Quantum and Molecular Structures, and Department of Physics
- Shanghai University
- Shanghai 200444
- China
| | - Riccarda Caputo
- International Centre for Quantum and Molecular Structures
- Shanghai University
- Shanghai 200444
- China
| | - Kaitong Sun
- Materials Genome Institute
- International Centre for Quantum and Molecular Structures, and Department of Physics
- Shanghai University
- Shanghai 200444
- China
| | - Yongchang Li
- Materials Genome Institute
- International Centre for Quantum and Molecular Structures, and Department of Physics
- Shanghai University
- Shanghai 200444
- China
| | - Guodong Zhao
- Materials Genome Institute
- International Centre for Quantum and Molecular Structures, and Department of Physics
- Shanghai University
- Shanghai 200444
- China
| | - Wei Ren
- Materials Genome Institute
- International Centre for Quantum and Molecular Structures, and Department of Physics
- Shanghai University
- Shanghai 200444
- China
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8
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Kamitani M, Bahramy MS, Nakajima T, Terakura C, Hashizume D, Arima T, Tokura Y. Superconductivity at the Polar-Nonpolar Phase Boundary of SnP with an Unusual Valence State. PHYSICAL REVIEW LETTERS 2017; 119:207001. [PMID: 29219367 DOI: 10.1103/physrevlett.119.207001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Indexed: 06/07/2023]
Abstract
Structural, magnetic, and electrical characterizations reveal that SnP with an unusual valence state (nominally Sn^{3+}) undergoes a ferroelectriclike structural transition from a simple NaCl-type structure to a polar tetragonal structure at approximately 250 K at ambient pressure. First-principles calculations indicate that the experimentally observed tetragonal distortion enhances the charge transfer from Sn to P, thereby making the polar tetragonal phase energetically more stable than the nonpolar cubic phase. Hydrostatic pressure is found to promptly suppress the structural phase transition in SnP, leading to the emergence of bulk superconductivity in a phase-competitive manner. These findings suggest that control of ferroelectriclike instability in a metal can be a promising way for creating novel superconductors.
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Affiliation(s)
- M Kamitani
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
| | - M S Bahramy
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
- Department of Applied Physics, University of Tokyo, Hongo, Tokyo 113-8656, Japan
| | - T Nakajima
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
| | - C Terakura
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
| | - D Hashizume
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
| | - T Arima
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
- Department of Advanced Materials Science, University of Tokyo, Kashiwa 277-8561, Japan
| | - Y Tokura
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
- Department of Applied Physics, University of Tokyo, Hongo, Tokyo 113-8656, Japan
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9
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Szczęśniak D, Wrona IA, Drzazga EA, Kaczmarek AZ, Szewczyk KA. On the critical temperature discontinuity at the theoretical bcc-fcc phase transition in compressed selenium and tellurium superconductors. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:445602. [PMID: 28850043 DOI: 10.1088/1361-648x/aa88ef] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Recent hydrides-driven advent in the high-pressure phonon-mediated superconductivity motivates research on chemical elements which compound with hydrogen. It is desired that such elements should allow chemical pre-compression of hydrogen to assure the induction of the superconducting phase with the high transition temperature (T C). Herein, we present detailed theoretical insight into the properties of the superconducting state induced under pressure (p) in two of such component elements, namely selenium (Se) and tellurium (Te) at [Formula: see text] GPa and [Formula: see text] GPa, respectively. The assumed external pressure conditions allow us to conduct our analysis just above previously theoretically predicted bcc-fcc structural phase transition of Se and Te, and identify the possible associated discontinuity effect of the critical temperature. In particular, our numerical analysis is conducted within Migdal-Eliashberg formalism, due to the confirmed electron-phonon pairing mechanism and relatively high electron-phonon coupling constant in the materials of interest. We predict that T C values in Se and Te equal 8.13 K and 5.96 K, respectively, and mark the highest critical temperature values for these elements within the postulated fcc phase. Additionally, we supplement these results by the estimated maximum values of the superconducting energy band gap and the effective mass of electrons. We predict that all these parameters can be used as a guidelines for experimental observation of the critical temperature discontinuity and the corresponding bcc-fcc phase transition in Se and Te superconductors. Moreover, we show that the thermodynamics of superconducting phase in both elements may exhibit deviations from the conventional estimates of the Bardeen-Cooper-Schrieffer theory, and suggest existence of the strong-coupling and retardation effects. Finally, we note that our results can be also instructive for future screening of chemical elements for applications in superconducting hydrides.
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Affiliation(s)
- D Szczęśniak
- Institute of Physics, Jan Długosz University in Częstochowa, Ave. Armii Krajowej 13/15, 42-200 Częstochowa, Poland
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10
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González-Romero RL, Antonelli A. Estimating carrier relaxation times in the Ba 8Ga 16Ge 30 clathrate in the extrinsic regime. Phys Chem Chem Phys 2017; 19:3010-3018. [PMID: 28079214 DOI: 10.1039/c6cp08026j] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We used a semi-empirical method to extract carrier relaxation times at different temperatures (τ(T)) in thermoelectric materials from a combination of experimental results and first-principles calculations. The methodology is based on the Boltzmann transport equation formalism within the relaxation time approximation. It can be applied to single crystals and polycrystalline materials. We applied the method to investigate the electronic transport properties of the clathrate compound Ba8Ga16Ge30 type-I. The calculations indicate that the carrier relaxation process in single crystals is dominated by electron-phonon scattering (τ ∝ T-3/2), while in polycrystalline materials scattering at grain boundaries dominates (τ ∼ cte). The Seebeck coefficient, electrical conductivity, and electron heat conduction are in consistent agreement with experiment. Furthermore, the Slack relation for lattice heat conductivity was successfully applied to the material. The calculated figure of merit is in good agreement with experimental results.
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Affiliation(s)
- Robert L González-Romero
- Instituto de Física "Gleb Wataghin" Universidade Estadual de Campinas, Caixa Postal 6165, CEP 13083-970, São Paulo, Brazil. and Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, 41013 Sevilla, Spain
| | - A Antonelli
- Instituto de Física "Gleb Wataghin" Universidade Estadual de Campinas, Caixa Postal 6165, CEP 13083-970, São Paulo, Brazil.
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11
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Hosono H, Tanabe K, Takayama-Muromachi E, Kageyama H, Yamanaka S, Kumakura H, Nohara M, Hiramatsu H, Fujitsu S. Exploration of new superconductors and functional materials, and fabrication of superconducting tapes and wires of iron pnictides. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2015; 16:033503. [PMID: 27877784 PMCID: PMC5099821 DOI: 10.1088/1468-6996/16/3/033503] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 04/28/2015] [Indexed: 06/02/2023]
Abstract
This review shows the highlights of a 4-year-long research project supported by the Japanese Government to explore new superconducting materials and relevant functional materials. The project found several tens of new superconductors by examining ∼1000 materials, each of which was chosen by Japanese experts with a background in solid state chemistry. This review summarizes the major achievements of the project in newly found superconducting materials, and the fabrication wires and tapes of iron-based superconductors; it incorporates a list of ∼700 unsuccessful materials examined for superconductivity in the project. In addition, described are new functional materials and functionalities discovered during the project.
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Affiliation(s)
- Hideo Hosono
- Frontier Research Center, Tokyo Institute of Technology, Yokohama 226-8503, Japan
- Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama 226-8503, Japan
- Materials Research Center for Element Strategy, Tokyo Institute of Technology, Yokohama 226-8503, Japan
| | - Keiichi Tanabe
- Superconductivity Research Laboratory, International Superconductivity Technology Center (ISTEC), 2-11-19 Minowa-cho, Kohoku-ku, Yokohama, Kanagawa 223-0051, Japan
| | | | - Hiroshi Kageyama
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Shoji Yamanaka
- Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527, Japan
| | - Hiroaki Kumakura
- National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
| | - Minoru Nohara
- Department of Physics, Okayama University, Okayama 700-8530, Japan
| | - Hidenori Hiramatsu
- Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama 226-8503, Japan
- Materials Research Center for Element Strategy, Tokyo Institute of Technology, Yokohama 226-8503, Japan
| | - Satoru Fujitsu
- Materials Research Center for Element Strategy, Tokyo Institute of Technology, Yokohama 226-8503, Japan
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12
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Raza Z, Errea I, Oganov AR, Saitta AM. Novel superconducting skutterudite-type phosphorus nitride at high pressure from first-principles calculations. Sci Rep 2014; 4:5889. [PMID: 25074347 PMCID: PMC4115206 DOI: 10.1038/srep05889] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 07/15/2014] [Indexed: 11/09/2022] Open
Abstract
State of the art variable composition structure prediction based on density functional theory demonstrates that two new stoichiometries of PN, PN3 and PN2, become viable at high pressure. PN3 has a skutterudite-like Immm structure and is metastable with positive phonon frequencies at pressures between 10 and 100 GPa. PN3 is metallic and is the first reported nitrogen-based skutterudite. Its metallicity arises from nitrogen p-states which delocalise across N4 rings characteristic of skutterudites, and it becomes a good electron-phonon superconductor at 10 GPa, with a Tc of around 18 K. The superconductivity arises from strongly enhanced electron-phonon coupling at lower pressures, originating primarily from soft collective P-N phonon modes. The PN2 phase is an insulator with P2/m symmetry and is stable at pressures in excess of 200 GPa.
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Affiliation(s)
- Zamaan Raza
- Sorbonne Universités, UPMC Univ. Paris 06, UMR 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), F-75005 Paris, France
- CNRS, UMR 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), F-75005 Paris, France
| | - Ion Errea
- Sorbonne Universités, UPMC Univ. Paris 06, UMR 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), F-75005 Paris, France
- Donostia International Physics Center (DIPC), Manuel de Lardizabal pasealekua 4, 20018 Donostia-San Sebastián, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain
| | - Artem R. Oganov
- Department of Geosciences, State University of New York, Stony Brook, NY 11794-2100, USA
- Center for Materials Design, Institute for Advanced Computational Science, State University of New York, Stony Brook, NY 11794-2011, USA
- Moscow Institute of Physics and Technology, 9 Institutskiy Lane, Dolgoprudny City, Moscow Region, 141700, Russian Federation
- Northwestern Polytechnical University, Xi'an, 710072, China
| | - A. Marco Saitta
- Sorbonne Universités, UPMC Univ. Paris 06, UMR 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), F-75005 Paris, France
- CNRS, UMR 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), F-75005 Paris, France
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13
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Kudo K, Takasuga M, Okamoto Y, Hiroi Z, Nohara M. Giant phonon softening and enhancement of superconductivity by phosphorus doping of BaNi2As2. PHYSICAL REVIEW LETTERS 2012; 109:097002. [PMID: 23002873 DOI: 10.1103/physrevlett.109.097002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Indexed: 05/05/2023]
Abstract
The effects of phosphorus doping on the structural and superconducting phase transitions of BaNi2(As(1-x)P(x))2 were studied. The specific heat, resistivity, and magnetic susceptibility were measured. The results revealed an abrupt increase in the superconducting transition temperature (T(c)) from 0.6 K in the triclinic phase (space group P1¯) with less phosphorus (x≤0.067) to 3.3 K in the tetragonal phase (space group I4/mmm) with more phosphorus (x≥0.067). Our data analysis suggests that a doping-induced softening related to an in-plane Ni and As(P) phonon mode is responsible for the enhanced superconductivity in the tetragonal phase.
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Affiliation(s)
- K Kudo
- Department of Physics, Okayama University, Okayama 700-8530, Japan.
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15
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Abstract
The ability of pressure to change inter-atomic distances strongly leads to a wide range of pressure-induced phenomena at high pressures: for example metallisation, amorphisation, superconductivity and polymerisation. Key to understanding these phenomena is the determination of the crystal structure using x-ray or neutron diffraction. The tools necessary to compress matter above 1 million atmospheres (1 Megabar or 100 GPa) were established by the mid 1970s, but it is only since the early 1990s that we have been able to determine the detailed crystal structures of materials at such pressures. In this chapter I briefly review the history of high-pressure crystallography, and describe the techniques used to obtain and study materials at high pressure. Recent crystallographic studies of elements are then used to illustrate what is now possible using modern detectors and synchrotron sources. Finally, I speculate as to what crystallographic studies might become possible over the next decade.
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Affiliation(s)
- Malcolm I McMahon
- SUPA, Centre for Science at Extreme Conditions, School of Physics and Astronomy, The University of Edinburgh, Edinburgh, EH9 3JZ, UK.
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16
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Sjakste J, Vast N, Tyuterev V. Ab initio method for calculating electron-phonon scattering times in semiconductors: application to GaAs and GaP. PHYSICAL REVIEW LETTERS 2007; 99:236405. [PMID: 18233390 DOI: 10.1103/physrevlett.99.236405] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2007] [Indexed: 05/25/2023]
Abstract
We propose a fully ab initio approach to calculate electron-phonon scattering times for excited electrons interacting with short-wavelength (intervalley) phonons in semiconductors. Our approach is based on density functional perturbation theory and on the direct integration of electronic scattering probabilities over all possible final states with no ad hoc assumptions. We apply it to the deexcitation of hot electrons in GaAs, and calculate the lifetime of the direct exciton in GaP, both in excellent agreement with experiments. Matrix elements of the electron-phonon coupling, and their dependence on the wave vector of the final state and on the phonon modes, are shown to be crucial ingredients of the evaluation of electron-phonon scattering times.
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Affiliation(s)
- Jelena Sjakste
- Ecole Polytechnique, Laboratoire des Solides Irradiés, CEA-DSM, CNRS, 91128 Palaiseau, France
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Zhang P, Louie SG, Cohen ML. Nonlocal screening, electron-phonon coupling, and phonon renormalization in metals. PHYSICAL REVIEW LETTERS 2005; 94:225502. [PMID: 16090410 DOI: 10.1103/physrevlett.94.225502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2004] [Indexed: 05/03/2023]
Abstract
A method for calculating the phonon self-energy in metals arising from the coupling between phonons and electrons near the Fermi surface is developed. The essence of this scheme is the separation of the inter- and intraband parts of the electron polarizability. The intraband contribution provides extra screenings and is closely related to the electron-phonon coupling and phonon softening in metals. Applications of this scheme to phonons in MgB2 give excellent results when compared with experiments and previous theoretical work. In addition, both electron and hole dopings are found to reduce the renormalization effect of the E(2g) phonon mode, which indicates a weakened electron-phonon coupling in the doped systems.
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Affiliation(s)
- Peihong Zhang
- Department of Physics, University of California at Berkeley, and Materials Sciences Division, Lawrence Berkeley Laboratory, Berkeley, CA 94720, USA
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18
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Hejny C, McMahon MI. Large structural modulations in incommensurate Te-III and Se-IV. PHYSICAL REVIEW LETTERS 2003; 91:215502. [PMID: 14683313 DOI: 10.1103/physrevlett.91.215502] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2003] [Indexed: 05/24/2023]
Abstract
The high-pressure phase of tellurium, Te-III, is found to have an incommensurate monoclinic structure, superspace group I(')2/m(0q0)s0, of a type previously unknown in the elements. Te-III is stable from 4.5(2) to 29.2(7) GPa; the previously reported transition to a distinct Te-IV phase at 10.6 GPa is not observed. The incommensurate wave vector of Te-III is strongly pressure dependent and varies in a strongly nonlinear way. Se-IV is found to be isostructural with Te-III.
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Affiliation(s)
- C Hejny
- School of Physics and Centre for Science at Extreme Conditions, The University of Edinburgh, Mayfield Road, Edinburgh EH9 3JZ, United Kingdom
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