1
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Pollak CJ, Skorupskii G, Gutierrez-Amigo M, Singha R, Stiles JW, Kamm F, Pielnhofer F, Ong NP, Errea I, Vergniory MG, Schoop LM. Chemical Bonding Induces One-Dimensional Physics in Bulk Crystal BiIr 4Se 8. J Am Chem Soc 2024; 146:6784-6795. [PMID: 38430128 DOI: 10.1021/jacs.3c13535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2024]
Abstract
One-dimensional (1D) systems persist as some of the most interesting because of the rich physics that emerges from constrained degrees of freedom. A desirable route to harness the properties therein is to grow bulk single crystals of a physically three-dimensional (3D) but electronically 1D compound. Most bulk compounds which approach the electronic 1D limit still field interactions across the other two crystallographic directions and, consequently, deviate from the 1D models. In this paper, we lay out chemical concepts to realize the physics of 1D models in 3D crystals. These are based on both structural and electronic arguments. We present BiIr4Se8, a bulk crystal consisting of linear Bi2+ chains within a scaffolding of IrSe6 octahedra, as a prime example. Through crystal structure analysis, density functional theory calculations, X-ray diffraction, and physical property measurements, we demonstrate the unique 1D electronic configuration in BiIr4Se8. This configuration at ambient temperature is a gapped Su-Schriefer-Heeger system, generated by way of a canonical Peierls distortion involving Bi dimerization that relieves instabilities in a 1D metallic state. At 190 K, an additional 1D charge density wave distortion emerges, which affects the Peierls distortion. The experimental evidence validates our design principles and distinguishes BiIr4Se8 among other quasi-1D bulk compounds. We thus show that it is possible to realize unique electronically 1D materials applying chemical concepts.
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Affiliation(s)
- Connor J Pollak
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Grigorii Skorupskii
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Martin Gutierrez-Amigo
- Department of Physics, University of the Basque Country (UPV/EHU), Bilbao 48080, Spain
- Centro de Física de Materiales (CSIC-UPV/EHU), Donostia/San Sebastián 20018, Spain
- Donostia International Physics Center (DIPC), Donostia/San Sebastián 20018, Spain
| | - Ratnadwip Singha
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Joseph W Stiles
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Franziska Kamm
- Department of Inorganic Chemistry, University of Regensburg, Regensburg 93040, Germany
| | - Florian Pielnhofer
- Department of Inorganic Chemistry, University of Regensburg, Regensburg 93040, Germany
| | - N P Ong
- Department of Physics, Princeton University, Princeton, New Jersey 08544, United States
| | - Ion Errea
- Centro de Física de Materiales (CSIC-UPV/EHU), Donostia/San Sebastián 20018, Spain
- Fisika Aplikatua Saila, Gipuzkoako Ingeniaritza Eskola, University of the Basque Country (UPV/EHU), Donostia/San Sebastián 20018, Spain
- Donostia International Physics Center (DIPC), Donostia/San Sebastián 20018, Spain
| | - Maia G Vergniory
- Donostia International Physics Center (DIPC), Donostia/San Sebastián 20018, Spain
- Max Planck Institute for Chemical Physics of Solids, Dresden 01187, Germany
| | - Leslie M Schoop
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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2
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Guo C, Wagner G, Putzke C, Chen D, Wang K, Zhang L, Gutierrez-Amigo M, Errea I, Vergniory MG, Felser C, Fischer MH, Neupert T, Moll PJW. Correlated order at the tipping point in the kagome metal CsV 3Sb 5. Nat Phys 2024; 20:579-584. [PMID: 38638456 PMCID: PMC11021193 DOI: 10.1038/s41567-023-02374-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 12/08/2023] [Indexed: 04/20/2024]
Abstract
Spontaneously broken symmetries are at the heart of many phenomena of quantum matter and physics more generally. However, determining the exact symmetries that are broken can be challenging due to imperfections such as strain, in particular when multiple electronic orders are competing. This is exemplified by charge order in some kagome systems, where evidence of nematicity and flux order from orbital currents remains inconclusive due to contradictory measurements. Here we clarify this controversy by fabricating highly symmetric samples of a member of this family, CsV3Sb5, and measuring their transport properties. We find that a measurable anisotropy is absent at any temperature in the unperturbed material. However, a pronounced in-plane transport anisotropy appears when either weak magnetic fields or strains are present. A symmetry analysis indicates that a perpendicular magnetic field can indeed lead to in-plane anisotropy by inducing a flux order coexisting with more conventional bond order. Our results provide a unifying picture for the controversial charge order in kagome metals and highlight the need for materials control at the microscopic scale in the identification of broken symmetries.
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Affiliation(s)
- Chunyu Guo
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany
| | - Glenn Wagner
- Department of Physics, University of Zürich, Zürich, Switzerland
| | - Carsten Putzke
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany
| | - Dong Chen
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
- College of Physics, Qingdao University, Qingdao, China
| | - Kaize Wang
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany
| | - Ling Zhang
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany
| | - Martin Gutierrez-Amigo
- Centro de Física de Materiales (CSIC-UPV/EHU), Donostia-San Sebastian, Spain
- Department of Physics, University of the Basque Country (UPV/EHU), Bilbao, Spain
| | - Ion Errea
- Centro de Física de Materiales (CSIC-UPV/EHU), Donostia-San Sebastian, Spain
- Donostia International Physics Center, Donostia-San Sebastian, Spain
- Fisika Aplikatua Saila, Gipuzkoako Ingeniaritza Eskola, University of the Basque Country (UPV/EHU), Donostia-San Sebastian, Spain
| | - Maia G. Vergniory
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
- Donostia International Physics Center, Donostia-San Sebastian, Spain
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
| | - Mark H. Fischer
- Department of Physics, University of Zürich, Zürich, Switzerland
| | - Titus Neupert
- Department of Physics, University of Zürich, Zürich, Switzerland
| | - Philip J. W. Moll
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany
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3
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Wan W, Harsh R, Meninno A, Dreher P, Sajan S, Guo H, Errea I, de Juan F, Ugeda MM. Evidence for ground state coherence in a two-dimensional Kondo lattice. Nat Commun 2023; 14:7005. [PMID: 37919299 PMCID: PMC10622499 DOI: 10.1038/s41467-023-42803-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 10/16/2023] [Indexed: 11/04/2023] Open
Abstract
Kondo lattices are ideal testbeds for the exploration of heavy-fermion quantum phases of matter. While our understanding of Kondo lattices has traditionally relied on complex bulk f-electron systems, transition metal dichalcogenide heterobilayers have recently emerged as simple, accessible and tunable 2D Kondo lattice platforms where, however, their ground state remains to be established. Here we present evidence of a coherent ground state in the 1T/1H-TaSe2 heterobilayer by means of scanning tunneling microscopy/spectroscopy at 340 mK. Our measurements reveal the existence of two symmetric electronic resonances around the Fermi energy, a hallmark of coherence in the spin lattice. Spectroscopic imaging locates both resonances at the central Ta atom of the charge density wave of the 1T phase, where the localized magnetic moment is held. Furthermore, the evolution of the electronic structure with the magnetic field reveals a non-linear increase of the energy separation between the electronic resonances. Aided by ab initio and auxiliary-fermion mean-field calculations, we demonstrate that this behavior is inconsistent with a fully screened Kondo lattice, and suggests a ground state with magnetic order mediated by conduction electrons. The manifestation of magnetic coherence in TMD-based 2D Kondo lattices enables the exploration of magnetic quantum criticality, Kondo breakdown transitions and unconventional superconductivity in the strict two-dimensional limit.
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Affiliation(s)
- Wen Wan
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal 4, 20018, San Sebastián, Spain
- Materials Genome Institute, Shanghai University, 200444, Shanghai, China
| | - Rishav Harsh
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal 4, 20018, San Sebastián, Spain
| | - Antonella Meninno
- Centro de Física de Materiales (CSIC-UPV/EHU), Paseo Manuel de Lardizábal 5, 20018, San Sebastián, Spain
- Departamento de Física Aplicada, Escuela de Ingeniería de Gipuzkoa, University of the Basque Country (UPV/EHU), Plaza Europa 1, 20018, San Sebastián, Spain
| | - Paul Dreher
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal 4, 20018, San Sebastián, Spain
| | - Sandra Sajan
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal 4, 20018, San Sebastián, Spain
| | - Haojie Guo
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal 4, 20018, San Sebastián, Spain
| | - Ion Errea
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal 4, 20018, San Sebastián, Spain
- Centro de Física de Materiales (CSIC-UPV/EHU), Paseo Manuel de Lardizábal 5, 20018, San Sebastián, Spain
- Departamento de Física Aplicada, Escuela de Ingeniería de Gipuzkoa, University of the Basque Country (UPV/EHU), Plaza Europa 1, 20018, San Sebastián, Spain
| | - Fernando de Juan
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal 4, 20018, San Sebastián, Spain.
- Ikerbasque, Basque Foundation for Science, 48013, Bilbao, Spain.
| | - Miguel M Ugeda
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal 4, 20018, San Sebastián, Spain.
- Centro de Física de Materiales (CSIC-UPV/EHU), Paseo Manuel de Lardizábal 5, 20018, San Sebastián, Spain.
- Ikerbasque, Basque Foundation for Science, 48013, Bilbao, Spain.
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4
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Liu C, Errea I, Ding C, Pickard C, Conway LJ, Monserrat B, Fang YW, Lu Q, Sun J, Boronat J, Cazorla C. Excitonic insulator to superconductor phase transition in ultra-compressed helium. Nat Commun 2023; 14:4458. [PMID: 37491484 PMCID: PMC10368699 DOI: 10.1038/s41467-023-40240-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 07/13/2023] [Indexed: 07/27/2023] Open
Abstract
Helium, the second most abundant element in the universe, exhibits an extremely large electronic band gap of about 20 eV at ambient pressures. While the metallization pressure of helium has been accurately determined, thus far little attention has been paid to the specific mechanisms driving the band-gap closure and electronic properties of this quantum crystal in the terapascal regime (1 TPa = 10 Mbar). Here, we employ density functional theory and many-body perturbation calculations to fill up this knowledge gap. It is found that prior to reaching metallicity helium becomes an excitonic insulator (EI), an exotic state of matter in which electrostatically bound electron-hole pairs may form spontaneously. Furthermore, we predict metallic helium to be a superconductor with a critical temperature of ≈ 20 K just above its metallization pressure and of ≈ 70 K at 100 TPa. These unforeseen phenomena may be critical for improving our fundamental understanding and modeling of celestial bodies.
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Affiliation(s)
- Cong Liu
- Departament de Física, Universitat Politècnica de Catalunya, Campus Nord B4-B5, Barcelona, 08034, Spain
| | - Ion Errea
- Fisika Aplikatua Saila, Gipuzkoako Ingeniaritza Eskola, University of the Basque Country (UPV/EHU), Europa Plaza 1, 20018, Donostia/San Sebastián, Spain
- Centro de Física de Materiales (CSIC-UPV/EHU), Manuel de Lardizabal pasealekua 5, 20018, Donostia/San Sebastián, Spain
- Donostia International Physics Center (DIPC), Manuel de Lardizabal pasealekua 4, 20018, Donostia/San Sebastián, Spain
| | - Chi Ding
- National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Chris Pickard
- Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, CB30FS, UK
- Advanced Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan
| | - Lewis J Conway
- Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, CB30FS, UK
- Advanced Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan
| | - Bartomeu Monserrat
- Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, CB30FS, UK
- Cavendish Laboratory, University of Cambridge, Cambridge, CB30HE, UK
| | - Yue-Wen Fang
- Fisika Aplikatua Saila, Gipuzkoako Ingeniaritza Eskola, University of the Basque Country (UPV/EHU), Europa Plaza 1, 20018, Donostia/San Sebastián, Spain
- Centro de Física de Materiales (CSIC-UPV/EHU), Manuel de Lardizabal pasealekua 5, 20018, Donostia/San Sebastián, Spain
| | - Qing Lu
- National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Jian Sun
- National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
| | - Jordi Boronat
- Departament de Física, Universitat Politècnica de Catalunya, Campus Nord B4-B5, Barcelona, 08034, Spain
| | - Claudio Cazorla
- Departament de Física, Universitat Politècnica de Catalunya, Campus Nord B4-B5, Barcelona, 08034, Spain.
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5
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Chen S, Leng PL, Konečná A, Modin E, Gutierrez-Amigo M, Vicentini E, Martín-García B, Barra-Burillo M, Niehues I, Maciel Escudero C, Xie XY, Hueso LE, Artacho E, Aizpurua J, Errea I, Vergniory MG, Chuvilin A, Xiu FX, Hillenbrand R. Real-space observation of ultraconfined in-plane anisotropic acoustic terahertz plasmon polaritons. Nat Mater 2023:10.1038/s41563-023-01547-8. [PMID: 37142739 DOI: 10.1038/s41563-023-01547-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 03/31/2023] [Indexed: 05/06/2023]
Abstract
Thin layers of in-plane anisotropic materials can support ultraconfined polaritons, whose wavelengths depend on the propagation direction. Such polaritons hold potential for the exploration of fundamental material properties and the development of novel nanophotonic devices. However, the real-space observation of ultraconfined in-plane anisotropic plasmon polaritons (PPs)-which exist in much broader spectral ranges than phonon polaritons-has been elusive. Here we apply terahertz nanoscopy to image in-plane anisotropic low-energy PPs in monoclinic Ag2Te platelets. The hybridization of the PPs with their mirror image-by placing the platelets above a Au layer-increases the direction-dependent relative polariton propagation length and the directional polariton confinement. This allows for verifying a linear dispersion and elliptical isofrequency contour in momentum space, revealing in-plane anisotropic acoustic terahertz PPs. Our work shows high-symmetry (elliptical) polaritons on low-symmetry (monoclinic) crystals and demonstrates the use of terahertz PPs for local measurements of anisotropic charge carrier masses and damping.
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Affiliation(s)
- S Chen
- Terahertz Technology Innovation Research Institute, National Basic Science Center-Terahertz Science and Technology Frontier, Terahertz Precision Biomedical Discipline 111 Project, Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, Shanghai, China
- CIC nanoGUNE BRTA, Donostia-San Sebastián, Spain
| | - P L Leng
- State Key Laboratory of Surface Physics and Department of Physics, Institute for Nanoelectronic Devices and Quantum Computing, Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai, China
| | - A Konečná
- Central European Institute of Technology, Brno University of Technology, Brno, Czech Republic
- Institute of Physical Engineering, Brno University of Technology, Brno, Czech Republic
| | - E Modin
- CIC nanoGUNE BRTA, Donostia-San Sebastián, Spain
| | - M Gutierrez-Amigo
- Materials Physics Center, CSIC-UPV/EHU, Donostia-San Sebastián, Spain
- Departamento de Física, Facultad de Ciencia y Tecnología, Universidad del País Vasco (UPV/EHU), Bilbao, Spain
| | - E Vicentini
- CIC nanoGUNE BRTA, Donostia-San Sebastián, Spain
| | - B Martín-García
- CIC nanoGUNE BRTA, Donostia-San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | | | - I Niehues
- CIC nanoGUNE BRTA, Donostia-San Sebastián, Spain
| | - C Maciel Escudero
- CIC nanoGUNE BRTA, Donostia-San Sebastián, Spain
- Materials Physics Center, CSIC-UPV/EHU, Donostia-San Sebastián, Spain
| | - X Y Xie
- State Key Laboratory of Surface Physics and Department of Physics, Institute for Nanoelectronic Devices and Quantum Computing, Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai, China
| | - L E Hueso
- CIC nanoGUNE BRTA, Donostia-San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - E Artacho
- CIC nanoGUNE BRTA, Donostia-San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
- Theory of Condensed Matter, Cavendish Laboratory, University of Cambridge, Cambridge, UK
- Donostia International Physics Centre (DIPC), Donostia-San Sebastián, Spain
| | - J Aizpurua
- Materials Physics Center, CSIC-UPV/EHU, Donostia-San Sebastián, Spain
- Donostia International Physics Centre (DIPC), Donostia-San Sebastián, Spain
| | - I Errea
- Materials Physics Center, CSIC-UPV/EHU, Donostia-San Sebastián, Spain
- Donostia International Physics Centre (DIPC), Donostia-San Sebastián, Spain
- Departamento de Física Aplicada, Escuela de Ingeniería de Gipuzkoa, Universidad del País Vasco (UPV/EHU), Donostia-San Sebastián, Spain
| | - M G Vergniory
- Donostia International Physics Centre (DIPC), Donostia-San Sebastián, Spain
- Max Planck for Chemical Physics of Solids, Dresden, Germany
| | - A Chuvilin
- CIC nanoGUNE BRTA, Donostia-San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - F X Xiu
- State Key Laboratory of Surface Physics and Department of Physics, Institute for Nanoelectronic Devices and Quantum Computing, Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai, China.
| | - R Hillenbrand
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
- CIC nanoGUNE BRTA and Department of Electricity and Electronics, UPV/EHU, Donostia-San Sebastián, Spain.
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6
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Wang H, Salzbrenner PT, Errea I, Peng F, Lu Z, Liu H, Zhu L, Pickard CJ, Yao Y. Quantum structural fluxion in superconducting lanthanum polyhydride. Nat Commun 2023; 14:1674. [PMID: 36966129 PMCID: PMC10039887 DOI: 10.1038/s41467-023-37295-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 03/09/2023] [Indexed: 03/27/2023] Open
Abstract
The discovery of 250-kelvin superconducting lanthanum polyhydride under high pressure marked a significant advance toward the realization of a room-temperature superconductor. X-ray diffraction (XRD) studies reveal a nonstoichiometric LaH9.6 or LaH10±δ polyhydride responsible for the superconductivity, which in the literature is commonly treated as LaH10 without accounting for stoichiometric defects. Here, we discover significant nuclear quantum effects (NQE) in this polyhydride, and demonstrate that a minor amount of stoichiometric defects will cause quantum proton diffusion in the otherwise rigid lanthanum lattice in the ground state. The diffusion coefficient reaches ~10-7 cm2/s in LaH9.63 at 150 gigapascals and 240 kelvin, approaching the upper bound value of interstitial hydrides at comparable temperatures. A puzzling phenomenon observed in previous experiments, the positive pressure dependence of the superconducting critical temperature Tc below 150 gigapascals, is explained by a modulation of the electronic structure due to a premature distortion of the hydrogen lattice in this quantum fluxional structure upon decompression, and resulting changes of the electron-phonon coupling. This finding suggests the coexistence of the quantum proton fluxion and hydrogen-induced superconductivity in this lanthanum polyhydride, and leads to an understanding of the structural nature and superconductivity of nonstoichiomectric hydrogen-rich materials.
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Affiliation(s)
- Hui Wang
- Key Laboratory for Photonic and Electronic Bandgap Materials (Ministry of Education), School of Physics and Electronic Engineering, Harbin Normal University, 150025, Harbin, China.
- International Center for Computational Method & Software, College of Physics, Jilin University, 130012, Changchun, China.
| | - Pascal T Salzbrenner
- Department of Materials Science & Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK
| | - Ion Errea
- Fisika Aplikatua Saila, Gipuzkoako Ingeniaritza Eskola, University of the Basque Country (UPV/EHU), Europa Plaza 1, 20018, Donostia/San Sebastián, Spain
- Centro de Física de Materiales (CSIC-UPV/EHU), Manuel de Lardizabal Pasealekua 5, 20018, Donostia/San Sebastián, Spain
- Donostia International Physics Center (DIPC), Manuel de Lardizabal Pasealekua 4, 20018, Donostia/San Sebastián, Spain
| | - Feng Peng
- College of Physics and Electronic Information, Luoyang Normal University, 471022, Luoyang, P. R. China
| | - Ziheng Lu
- Department of Materials Science & Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK
| | - Hanyu Liu
- International Center for Computational Method & Software, College of Physics, Jilin University, 130012, Changchun, China
- State Key Laboratory of Superhard Materials and International Center of Future Science, Jilin University, 130012, Changchun, China
| | - Li Zhu
- Department of Physics, Rutgers University, Newark, NJ, 07102, USA
| | - Chris J Pickard
- Department of Materials Science & Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK
- Advanced Institute for Materials Research, Tohoku University 2-1-1 Katahira, Aoba, Sendai, 980-8577, Japan
| | - Yansun Yao
- Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5E2, Canada
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7
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Fumega AO, Diego J, Pardo V, Blanco-Canosa S, Errea I. Anharmonicity Reveals the Tunability of the Charge Density Wave Orders in Monolayer VSe 2. Nano Lett 2023; 23:1794-1800. [PMID: 36825982 PMCID: PMC9999451 DOI: 10.1021/acs.nanolett.2c04584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 02/22/2023] [Indexed: 06/18/2023]
Abstract
VSe2 is a layered compound that has attracted great attention due to its proximity to a ferromagnetic state that is quenched by its charge density wave (CDW) phase. In the monolayer limit, unrelated experiments have reported different CDW orders with different transition temperatures, making this monolayer very controversial. Here we perform first-principles nonperturbative anharmonic phonon calculations in monolayer VSe2 in order to estimate the CDW order and the corresponding transition temperature. They reveal that monolayer VSe2 develops two independent charge density wave orders that compete as a function of strain. Variations of only 1.5% in the lattice parameter are enough to stabilize one order or the other. Moreover, we analyze the impact of external Lennard-Jones interactions, showing that these can act together with anharmonicity to suppress the CDW orders. Our results solve previous experimental contradictions, highlighting the high tunability and substrate dependency of the CDW orders of monolayer VSe2.
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Affiliation(s)
| | - Josu Diego
- Fisika
Aplikatua Saila, Gipuzkoako Ingeniaritza Eskola, University of the Basque Country (UPV/EHU), 20018 San Sebastián, Spain
- Centro
de Física de Materiales (CSIC-UPV/EHU), 20018 San Sebastián, Spain
| | - Victor Pardo
- Departamento
de Física Aplicada, Universidade
de Santiago de Compostela, 15782 Santiago de Compostela, Spain
- Instituto
de Materiais iMATUS, Universidade de Santiago
de Compostela, 15782 Santiago de Compostela, Spain
| | - Santiago Blanco-Canosa
- Donostia
International Physics Center (DIPC), 20018 San Sebastián, Spain
- IKERBASQUE, Basque Foundation
for Science, 48013 Bilbao, Spain
| | - Ion Errea
- Fisika
Aplikatua Saila, Gipuzkoako Ingeniaritza Eskola, University of the Basque Country (UPV/EHU), 20018 San Sebastián, Spain
- Centro
de Física de Materiales (CSIC-UPV/EHU), 20018 San Sebastián, Spain
- Donostia
International Physics Center (DIPC), 20018 San Sebastián, Spain
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8
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Guo C, Putzke C, Konyzheva S, Huang X, Gutierrez-Amigo M, Errea I, Chen D, Vergniory MG, Felser C, Fischer MH, Neupert T, Moll PJW. Switchable chiral transport in charge-ordered kagome metal CsV 3Sb 5. Nature 2022; 611:461-466. [PMID: 36224393 PMCID: PMC9668744 DOI: 10.1038/s41586-022-05127-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 07/20/2022] [Indexed: 11/08/2022]
Abstract
When electric conductors differ from their mirror image, unusual chiral transport coefficients appear that are forbidden in achiral metals, such as a non-linear electric response known as electronic magnetochiral anisotropy (eMChA)1-6. Although chiral transport signatures are allowed by symmetry in many conductors without a centre of inversion, they reach appreciable levels only in rare cases in which an exceptionally strong chiral coupling to the itinerant electrons is present. So far, observations of chiral transport have been limited to materials in which the atomic positions strongly break mirror symmetries. Here, we report chiral transport in the centrosymmetric layered kagome metal CsV3Sb5 observed via second-harmonic generation under an in-plane magnetic field. The eMChA signal becomes significant only at temperatures below [Formula: see text] 35 K, deep within the charge-ordered state of CsV3Sb5 (TCDW ≈ 94 K). This temperature dependence reveals a direct correspondence between electronic chirality, unidirectional charge order7 and spontaneous time-reversal symmetry breaking due to putative orbital loop currents8-10. We show that the chirality is set by the out-of-plane field component and that a transition from left- to right-handed transport can be induced by changing the field sign. CsV3Sb5 is the first material in which strong chiral transport can be controlled and switched by small magnetic field changes, in stark contrast to structurally chiral materials, which is a prerequisite for applications in chiral electronics.
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Affiliation(s)
- Chunyu Guo
- Laboratory of Quantum Materials (QMAT), Institute of Materials (IMX), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany.
| | - Carsten Putzke
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany
| | - Sofia Konyzheva
- Laboratory of Quantum Materials (QMAT), Institute of Materials (IMX), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Xiangwei Huang
- Laboratory of Quantum Materials (QMAT), Institute of Materials (IMX), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Martin Gutierrez-Amigo
- Centro de Física de Materiales (CSIC-UPV/EHU), Donostia-San Sebastian, Spain
- Department of Physics, University of the Basque Country (UPV/EHU), Bilbao, Spain
| | - Ion Errea
- Centro de Física de Materiales (CSIC-UPV/EHU), Donostia-San Sebastian, Spain
- Donostia International Physics Center, Donostia-San Sebastian, Spain
- Fisika Aplikatua Saila, Gipuzkoako Ingeniaritza Eskola, University of the Basque Country (UPV/EHU), Donostia-San Sebastian, Spain
| | - Dong Chen
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
- College of Physics, Qingdao University, Qingdao, China
| | - Maia G Vergniory
- Donostia International Physics Center, Donostia-San Sebastian, Spain
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
| | - Mark H Fischer
- Department of Physics, University of Zürich, Zürich, Switzerland.
| | - Titus Neupert
- Department of Physics, University of Zürich, Zürich, Switzerland.
| | - Philip J W Moll
- Laboratory of Quantum Materials (QMAT), Institute of Materials (IMX), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany.
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9
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Won J, Kim S, Gutierrez‐Amigo M, Bettler S, Lee B, Son J, Won Noh T, Errea I, Vergniory MG, Abbamonte P, Mahmood F, Shoemaker DP. Transport and optical properties of the chiral semiconductor Ag
3
AuSe
2. Z Anorg Allg Chem 2022. [DOI: 10.1002/zaac.202200055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Juyeon Won
- Department of Materials Science and Engineering and Materials Research Laboratory University of Illinois at Urbana-Champaign Urbana IL 61801 USA
| | - Soyeun Kim
- Department of Physics University of Illinois at Urbana-Champaign Urbana 61801 IL USA
- Materials Research Laboratory University of Illinois at Urbana-Champaign Urbana 61801 IL USA
| | - Martin Gutierrez‐Amigo
- Department of Physics University of the Basque Country (UPV/EHU) Apartado 644 48080 Bilbao Spain
- Centro de Física de Materiales (CSIC-UPV/EHU) Manuel de Lardizabal Pasealekua 5 20018 Donostia/San Sebastián Spain
| | - Simon Bettler
- Department of Physics University of Illinois at Urbana-Champaign Urbana 61801 IL USA
- Materials Research Laboratory University of Illinois at Urbana-Champaign Urbana 61801 IL USA
| | - Bumjoo Lee
- Center for Correlated Electron Systems Institute for Basic Science Seoul 08826 Republic of Korea
- Department of Physics and Astronomy Seoul National University Seoul 08826 Republic of Korea
| | - Jaeseok Son
- Center for Correlated Electron Systems Institute for Basic Science Seoul 08826 Republic of Korea
- Department of Physics and Astronomy Seoul National University Seoul 08826 Republic of Korea
| | - Tae Won Noh
- Center for Correlated Electron Systems Institute for Basic Science Seoul 08826 Republic of Korea
- Department of Physics and Astronomy Seoul National University Seoul 08826 Republic of Korea
| | - Ion Errea
- Centro de Física de Materiales (CSIC-UPV/EHU) Manuel de Lardizabal Pasealekua 5 20018 Donostia/San Sebastián Spain
- Donostia International Physics Center P. Manuel de Lardizabal 4 20018 Donostia-San Sebastian Spain
- Fisika Aplikatua Saila, Gipuzkoako Ingeniaritza Eskola University of the Basque Country (UPV/EHU) Europa Plaza 1 20018 Donostia/San Sebastián Spain
| | - Maia G. Vergniory
- Donostia International Physics Center P. Manuel de Lardizabal 4 20018 Donostia-San Sebastian Spain
- Max Planck Institute for Chemical Physics of Solids 01187 Dresden Germany
| | - Peter Abbamonte
- Department of Physics University of Illinois at Urbana-Champaign Urbana 61801 IL USA
- Materials Research Laboratory University of Illinois at Urbana-Champaign Urbana 61801 IL USA
| | - Fahad Mahmood
- Department of Physics University of Illinois at Urbana-Champaign Urbana 61801 IL USA
- Materials Research Laboratory University of Illinois at Urbana-Champaign Urbana 61801 IL USA
| | - Daniel P. Shoemaker
- Department of Materials Science and Engineering and Materials Research Laboratory University of Illinois at Urbana-Champaign Urbana IL 61801 USA
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10
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Abstract
Reaching superconductivity at ambient conditions is one of the biggest scientific dreams. The discoveries in the last few years at high pressures place hydrogen-based compounds as the best candidates for making it true. As the recent history shows, first-principles calculations are expected to continue guiding the experimental quest in the right track in the coming years. Considering that ionic quantum fluctuations largely affect the crystal structure and the vibrational properties of superconducting hydrides, in many cases making them thermodynamically stable at much lower pressures than expected, it will be crucial to include such effects on the futureab initiopredictions. The prospects for low-pressure high critical-temperature compounds are wide open, even at ambient pressure.
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Affiliation(s)
- Ion Errea
- Fisika Aplikatua Saila, Gipuzkoako Ingeniaritza Eskola, University of the Basque Country (UPV/EHU), Europa Plaza 1, 20018 Donostia/San Sebastián, Spain
- Centro de Física de Materiales (CSIC-UPV/EHU), Manuel de Lardizabal pasealekua 5, 20018 Donostia/San Sebastián, Spain
- Donostia International Physics Center (DIPC), Manuel de Lardizabal pasealekua 4, 20018 Donostia/San Sebastián, Spain
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11
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Boeri L, Hennig R, Hirschfeld P, Profeta G, Sanna A, Zurek E, Pickett WE, Amsler M, Dias R, Eremets MI, Heil C, Hemley RJ, Liu H, Ma Y, Pierleoni C, Kolmogorov AN, Rybin N, Novoselov D, Anisimov V, Oganov AR, Pickard CJ, Bi T, Arita R, Errea I, Pellegrini C, Requist R, Gross EKU, Margine ER, Xie SR, Quan Y, Hire A, Fanfarillo L, Stewart GR, Hamlin JJ, Stanev V, Gonnelli RS, Piatti E, Romanin D, Daghero D, Valenti R. The 2021 room-temperature superconductivity roadmap. J Phys Condens Matter 2022; 34:183002. [PMID: 34544070 DOI: 10.1088/1361-648x/ac2864] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 09/20/2021] [Indexed: 06/13/2023]
Abstract
Designing materials with advanced functionalities is the main focus of contemporary solid-state physics and chemistry. Research efforts worldwide are funneled into a few high-end goals, one of the oldest, and most fascinating of which is the search for an ambient temperature superconductor (A-SC). The reason is clear: superconductivity at ambient conditions implies being able to handle, measure and access a single, coherent, macroscopic quantum mechanical state without the limitations associated with cryogenics and pressurization. This would not only open exciting avenues for fundamental research, but also pave the road for a wide range of technological applications, affecting strategic areas such as energy conservation and climate change. In this roadmap we have collected contributions from many of the main actors working on superconductivity, and asked them to share their personal viewpoint on the field. The hope is that this article will serve not only as an instantaneous picture of the status of research, but also as a true roadmap defining the main long-term theoretical and experimental challenges that lie ahead. Interestingly, although the current research in superconductor design is dominated by conventional (phonon-mediated) superconductors, there seems to be a widespread consensus that achieving A-SC may require different pairing mechanisms.In memoriam, to Neil Ashcroft, who inspired us all.
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Affiliation(s)
- Lilia Boeri
- Physics Department, Sapienza University and Enrico Fermi Research Center, Rome, Italy
| | - Richard Hennig
- Deparment of Material Science and Engineering and Quantum Theory Project, University of Florida, Gainesville 32611, United States of America
| | - Peter Hirschfeld
- Department of Physics, University of Florida, Gainesville, FL 32611, United States of America
| | | | - Antonio Sanna
- Max Planck Institute of Microstructure Physics, Halle, Germany
| | - Eva Zurek
- University at Buffalo, SUNY, United States of America
| | | | - Maximilian Amsler
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14853, United States of America
| | - Ranga Dias
- University of Rochester, United States of America
| | | | | | | | - Hanyu Liu
- Jilin University, People's Republic of China
| | - Yanming Ma
- Jilin University, People's Republic of China
| | - Carlo Pierleoni
- Department of Physics, University of Florida, Gainesville, FL 32611, United States of America
| | | | | | | | | | | | | | - Tiange Bi
- University at Buffalo, SUNY, United States of America
| | | | - Ion Errea
- University of the Basque Country, Spain
| | | | - Ryan Requist
- Max Planck Institute of Microstructure Physics, Halle, Germany
- Hebrew University of Jerusalem, Israel
| | - E K U Gross
- Max Planck Institute of Microstructure Physics, Halle, Germany
- Hebrew University of Jerusalem, Israel
| | | | - Stephen R Xie
- Department of Physics, University of Florida, Gainesville, FL 32611, United States of America
| | - Yundi Quan
- Department of Physics, University of Florida, Gainesville, FL 32611, United States of America
| | - Ajinkya Hire
- Department of Physics, University of Florida, Gainesville, FL 32611, United States of America
| | - Laura Fanfarillo
- Department of Physics, University of Florida, Gainesville, FL 32611, United States of America
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Via Bonomea 265, 34136 Trieste, Italy
| | - G R Stewart
- Department of Physics, University of Florida, Gainesville, FL 32611, United States of America
| | - J J Hamlin
- Department of Physics, University of Florida, Gainesville, FL 32611, United States of America
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12
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Romanin D, Monacelli L, Bianco R, Errea I, Mauri F, Calandra M. Dominant Role of Quantum Anharmonicity in the Stability and Optical Properties of Infinite Linear Acetylenic Carbon Chains. J Phys Chem Lett 2021; 12:10339-10345. [PMID: 34664958 DOI: 10.1021/acs.jpclett.1c02964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Carbyne, an infinite-length straight chain of carbon atoms, is supposed to undergo a second order phase transition from the metallic bond-symmetric cumulene (═C═C═)∞ toward the distorted insulating polyyne chain (-C≡C-)∞ displaying bond-length alternation. However, recent synthesis of ultra long carbon chains (∼6000 atoms, [Nat. Mater., 2016, 15, 634]) did not show any phase transition and detected only the polyyne phase, in agreement with previous experiments on capped finite carbon chains. Here, by performing first-principles calculations, we show that quantum-anharmonicity reduces the energy gain of the polyyne phase with respect to the cumulene one by 71%. The magnitude of the bond-length alternation increases by increasing temperature, in stark contrast with a second order phase transition, confining the cumulene-to-polyyne transition to extremely high and unphysical temperatures. Finally, we predict that a high temperature insulator-to-metal transition occurs in the polyyne phase confined in insulating nanotubes with sufficiently large dielectric constant due to a giant quantum-anharmonic bandgap renormalization.
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Affiliation(s)
- Davide Romanin
- Institut des Nanosciences de Paris, UMR7588, Sorbonne Université, CNRS, F-75252, Paris, France
| | - Lorenzo Monacelli
- Dipartimento di Fisica, Universitá di Roma La Sapienza, Piazzale Aldo Moro 5, I-00185 Rome, Italy
| | - Raffaello Bianco
- Centro de Física de Materiales (CSIC-UPV/EHU), Manuel de Lardizabal pasealekua 5, 20018 Donostia-San Sebastián, Basque Country, Spain
| | - Ion Errea
- Centro de Física de Materiales (CSIC-UPV/EHU), Manuel de Lardizabal pasealekua 5, 20018 Donostia-San Sebastián, Basque Country, Spain
- Fisika Aplikatua 1 Saila, Gipuzkoako Ingeniaritza Eskola, University of the Basque Country (UPV/EHU), Europa Plaza 1, 20018, Donostia San Sebastián, Basque Country, Spain
| | - Francesco Mauri
- Dipartimento di Fisica, Universitá di Roma La Sapienza, Piazzale Aldo Moro 5, I-00185 Rome, Italy
| | - Matteo Calandra
- Institut des Nanosciences de Paris, UMR7588, Sorbonne Université, CNRS, F-75252, Paris, France
- Department of Physics, University of Trento, Via Sommarive 14, 38123 Povo, Italy
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13
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Belli F, Novoa T, Contreras-García J, Errea I. Strong correlation between electronic bonding network and critical temperature in hydrogen-based superconductors. Nat Commun 2021; 12:5381. [PMID: 34531389 PMCID: PMC8446067 DOI: 10.1038/s41467-021-25687-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 08/25/2021] [Indexed: 02/08/2023] Open
Abstract
By analyzing structural and electronic properties of more than a hundred predicted hydrogen-based superconductors, we determine that the capacity of creating an electronic bonding network between localized units is key to enhance the critical temperature in hydrogen-based superconductors. We define a magnitude named as the networking value, which correlates with the predicted critical temperature better than any other descriptor analyzed thus far. By classifying the studied compounds according to their bonding nature, we observe that such correlation is bonding-type independent, showing a broad scope and generality. Furthermore, combining the networking value with the hydrogen fraction in the system and the hydrogen contribution to the density of states at the Fermi level, we can predict the critical temperature of hydrogen-based compounds with an accuracy of about 60 K. Such correlation is useful to screen new superconducting compounds and offers a deeper understating of the chemical and physical properties of hydrogen-based superconductors, while setting clear paths for chemically engineering their critical temperatures.
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Affiliation(s)
- Francesco Belli
- grid.482265.f0000 0004 1762 5146Centro de Física de Materiales (CSIC-UPV/EHU), Donostia/San Sebastián, Spain ,grid.11480.3c0000000121671098Fisika Aplikatua Saila, Gipuzkoako Ingeniaritza Eskola, University of the Basque Country (UPV/EHU), Donostia/San Sebastián, Spain
| | - Trinidad Novoa
- grid.462844.80000 0001 2308 1657Laboratoire de Chimie Théorique (LCT), Sorbonne Université CNRS, Paris, France
| | - J. Contreras-García
- grid.462844.80000 0001 2308 1657Laboratoire de Chimie Théorique (LCT), Sorbonne Université CNRS, Paris, France
| | - Ion Errea
- grid.482265.f0000 0004 1762 5146Centro de Física de Materiales (CSIC-UPV/EHU), Donostia/San Sebastián, Spain ,grid.11480.3c0000000121671098Fisika Aplikatua Saila, Gipuzkoako Ingeniaritza Eskola, University of the Basque Country (UPV/EHU), Donostia/San Sebastián, Spain ,grid.452382.a0000 0004 1768 3100Donostia International Physics Center (DIPC), Donostia/San Sebastián, Spain
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14
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Monacelli L, Bianco R, Cherubini M, Calandra M, Errea I, Mauri F. The stochastic self-consistent harmonic approximation: calculating vibrational properties of materials with full quantum and anharmonic effects. J Phys Condens Matter 2021; 33:363001. [PMID: 34049302 DOI: 10.1088/1361-648x/ac066b] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 05/28/2021] [Indexed: 06/12/2023]
Abstract
The efficient and accurate calculation of how ionic quantum and thermal fluctuations impact the free energy of a crystal, its atomic structure, and phonon spectrum is one of the main challenges of solid state physics, especially when strong anharmonicy invalidates any perturbative approach. To tackle this problem, we present the implementation on a modular Python code of the stochastic self-consistent harmonic approximation (SSCHA) method. This technique rigorously describes the full thermodynamics of crystals accounting for nuclear quantum and thermal anharmonic fluctuations. The approach requires the evaluation of the Born-Oppenheimer energy, as well as its derivatives with respect to ionic positions (forces) and cell parameters (stress tensor) in supercells, which can be provided, for instance, by first principles density-functional-theory codes. The method performs crystal geometry relaxation on the quantum free energy landscape, optimizing the free energy with respect to all degrees of freedom of the crystal structure. It can be used to determine the phase diagram of any crystal at finite temperature. It enables the calculation of phase boundaries for both first-order and second-order phase transitions from the Hessian of the free energy. Finally, the code can also compute the anharmonic phonon spectra, including the phonon linewidths, as well as phonon spectral functions. We review the theoretical framework of the SSCHA and its dynamical extension, making particular emphasis on the physical inter pretation of the variables present in the theory that can enlighten the comparison with any other anharmonic theory. A modular and flexible Python environment is used for the implementation, which allows for a clean interaction with other packages. We briefly present a toy-model calculation to illustrate the potential of the code. Several applications of the method in superconducting hydrides, charge-density-wave materials, and thermoelectric compounds are also reviewed.
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Affiliation(s)
- Lorenzo Monacelli
- Dipartimento di Fisica, Università di Roma Sapienza, Piazzale Aldo Moro 5, 00185 Roma, Italy
| | - Raffaello Bianco
- Centro de Física de Materiales (CSIC-UPV/EHU), Manuel de Lardizabal pasealekua 5, 20018 Donostia/San Sebastián, Spain
| | - Marco Cherubini
- Dipartimento di Fisica, Università di Roma Sapienza, Piazzale Aldo Moro 5, 00185 Roma, Italy
- Center for Life NanoScience, Istituto Italiano di Tecnologia, Viale ReginaElena 291, 00161 Rome, Italy
| | - Matteo Calandra
- Sorbonne Université, CNRS, Institut des Nanosciences de Paris, UMR7588, F-75252 Paris, France
- Dipartimento di Fisica, Universitá di Trento, Via Sommarive 14, 38123 Povo, Italy
| | - Ion Errea
- Centro de Física de Materiales (CSIC-UPV/EHU), Manuel de Lardizabal pasealekua 5, 20018 Donostia/San Sebastián, Spain
- Fisika Aplikatua Saila, Gipuzkoako Ingeniaritza Eskola, University of the Basque Country (UPV/EHU), Europa Plaza 1, 20018 Donostia/San Sebastián, Spain
- Donostia International Physics Center (DIPC), Manuel Lardizabal pasealekua 4, 20018 Donostia/San Sebastián, Spain
| | - Francesco Mauri
- Dipartimento di Fisica, Università di Roma Sapienza, Piazzale Aldo Moro 5, 00185 Roma, Italy
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15
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Troyan IA, Semenok DV, Kvashnin AG, Sadakov AV, Sobolevskiy OA, Pudalov VM, Ivanova AG, Prakapenka VB, Greenberg E, Gavriliuk AG, Lyubutin IS, Struzhkin VV, Bergara A, Errea I, Bianco R, Calandra M, Mauri F, Monacelli L, Akashi R, Oganov AR. Anomalous High-Temperature Superconductivity in YH 6. Adv Mater 2021; 33:e2006832. [PMID: 33751670 DOI: 10.1002/adma.202006832] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/25/2020] [Indexed: 06/12/2023]
Abstract
Pressure-stabilized hydrides are a new rapidly growing class of high-temperature superconductors, which is believed to be described within the conventional phonon-mediated mechanism of coupling. Here, the synthesis of one of the best-known high-TC superconductors-yttrium hexahydride I m 3 ¯ m -YH6 is reported, which displays a superconducting transition at ≈224 K at 166 GPa. The extrapolated upper critical magnetic field Bc2 (0) of YH6 is surprisingly high: 116-158 T, which is 2-2.5 times larger than the calculated value. A pronounced shift of TC in yttrium deuteride YD6 with the isotope coefficient 0.4 supports the phonon-assisted superconductivity. Current-voltage measurements show that the critical current IC and its density JC may exceed 1.75 A and 3500 A mm-2 at 4 K, respectively, which is higher than that of the commercial superconductors, such as NbTi and YBCO. The results of superconducting density functional theory (SCDFT) and anharmonic calculations, together with anomalously high critical magnetic field, suggest notable departures of the superconducting properties from the conventional Migdal-Eliashberg and Bardeen-Cooper-Schrieffer theories, and presence of an additional mechanism of superconductivity.
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Affiliation(s)
- Ivan A Troyan
- Shubnikov Institute of Crystallography, Federal Scientific Research Center Crystallography and Photonics, Russian Academy of Sciences, 59 Leninskii Prospect, Moscow, 119333, Russia
| | - Dmitrii V Semenok
- Skolkovo Institute of Science and Technology, Skolkovo Innovation Center, 3 Nobel Street, Moscow, 121025, Russia
| | - Alexander G Kvashnin
- Skolkovo Institute of Science and Technology, Skolkovo Innovation Center, 3 Nobel Street, Moscow, 121025, Russia
| | - Andrey V Sadakov
- P.N. Lebedev Physical Institute, Russian Academy of Sciences, Moscow, 119991, Russia
| | - Oleg A Sobolevskiy
- P.N. Lebedev Physical Institute, Russian Academy of Sciences, Moscow, 119991, Russia
| | - Vladimir M Pudalov
- P.N. Lebedev Physical Institute, Russian Academy of Sciences, Moscow, 119991, Russia
- National Research University, Higher School of Economics, Moscow, 101000, Russia
| | - Anna G Ivanova
- Shubnikov Institute of Crystallography, Federal Scientific Research Center Crystallography and Photonics, Russian Academy of Sciences, 59 Leninskii Prospect, Moscow, 119333, Russia
| | - Vitali B Prakapenka
- Center for Advanced Radiation Sources, The University of Chicago, 5640 South Ellis Avenue, Chicago, IL, 60637, USA
| | - Eran Greenberg
- Center for Advanced Radiation Sources, The University of Chicago, 5640 South Ellis Avenue, Chicago, IL, 60637, USA
| | - Alexander G Gavriliuk
- Shubnikov Institute of Crystallography, Federal Scientific Research Center Crystallography and Photonics, Russian Academy of Sciences, 59 Leninskii Prospect, Moscow, 119333, Russia
- Institute for Nuclear Research, Russian Academy of Sciences, Fizicheskaya str. 27, Troitsk, Moscow, 108840, Russia
| | - Igor S Lyubutin
- Shubnikov Institute of Crystallography, Federal Scientific Research Center Crystallography and Photonics, Russian Academy of Sciences, 59 Leninskii Prospect, Moscow, 119333, Russia
| | - Viktor V Struzhkin
- Center for High Pressure Science and Technology Advanced Research, Shanghai, 201203, China
| | - Aitor Bergara
- Centro de Física de Materiales CFM, CSIC-UPV/EHU, Paseo Manuel de Lardizabal 5, Basque Country, Donostia, 20018, Spain
- Departamento de Física de la Materia Condensada, University of the Basque Country (UPV/EHU), Basque Country, Bilbao, 48080, Spain
- Donostia International Physics Center (DIPC), Manuel Lardizabal pasealekua 4, Basque Country, Donostia, 20018, Spain
| | - Ion Errea
- Centro de Física de Materiales CFM, CSIC-UPV/EHU, Paseo Manuel de Lardizabal 5, Basque Country, Donostia, 20018, Spain
- Donostia International Physics Center (DIPC), Manuel Lardizabal pasealekua 4, Basque Country, Donostia, 20018, Spain
- Fisika Aplikatua 1 Saila, University of the Basque Country (UPV/EHU), Europa plaza 1, Donostia, 20018, Spain
| | - Raffaello Bianco
- Centro de Física de Materiales CFM, CSIC-UPV/EHU, Paseo Manuel de Lardizabal 5, Basque Country, Donostia, 20018, Spain
| | - Matteo Calandra
- Departimento di Fisica, Università di Trento, Via Sommarive 14, Povo, 38123, Italy
- Sorbonne Université, CNRS, Institut des Nanosciences de Paris, UMR7588, Paris, F-75252, France
- Graphene Labs, Fondazione Istituto Italiano di Tecnologia, Via Morego, Genova, I-16163, Italy
| | - Francesco Mauri
- Sorbonne Université, CNRS, Institut des Nanosciences de Paris, UMR7588, Paris, F-75252, France
- Graphene Labs, Fondazione Istituto Italiano di Tecnologia, Via Morego, Genova, I-16163, Italy
| | - Lorenzo Monacelli
- Graphene Labs, Fondazione Istituto Italiano di Tecnologia, Via Morego, Genova, I-16163, Italy
- Dipartimento di Fisica, Università di Roma Sapienza, Piazzale Aldo Moro 5, Roma, I-00185, Italy
| | - Ryosuke Akashi
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-8654, Japan
| | - Artem R Oganov
- Skolkovo Institute of Science and Technology, Skolkovo Innovation Center, 3 Nobel Street, Moscow, 121025, Russia
- Dipartimento di Fisica, Università di Roma Sapienza, Piazzale Aldo Moro 5, Roma, I-00185, Italy
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-8654, Japan
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16
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de Oliveira TVAG, Nörenberg T, Álvarez-Pérez G, Wehmeier L, Taboada-Gutiérrez J, Obst M, Hempel F, Lee EJH, Klopf JM, Errea I, Nikitin AY, Kehr SC, Alonso-González P, Eng LM. Nanoscale-Confined Terahertz Polaritons in a van der Waals Crystal. Adv Mater 2021; 33:e2005777. [PMID: 33270287 DOI: 10.1002/adma.202005777] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/16/2020] [Indexed: 05/28/2023]
Abstract
Electromagnetic field confinement is crucial for nanophotonic technologies, since it allows for enhancing light-matter interactions, thus enabling light manipulation in deep sub-wavelength scales. In the terahertz (THz) spectral range, radiation confinement is conventionally achieved with specially designed metallic structures-such as antennas or nanoslits-with large footprints due to the rather long wavelengths of THz radiation. In this context, phonon polaritons-light coupled to lattice vibrations-in van der Waals (vdW) crystals have emerged as a promising solution for controlling light beyond the diffraction limit, as they feature extreme field confinements and low optical losses. However, experimental demonstration of nanoscale-confined phonon polaritons at THz frequencies has so far remained elusive. Here, it is provided by employing scattering-type scanning near-field optical microscopy combined with a free-electron laser to reveal a range of low-loss polaritonic excitations at frequencies from 8 to 12 THz in the vdW semiconductor α-MoO3 . In this study, THz polaritons are visualized with: i) in-plane hyperbolic dispersion, ii) extreme nanoscale field confinement (below λo ⁄75), and iii) long polariton lifetimes, with a lower limit of >2 ps.
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Affiliation(s)
- Thales V A G de Oliveira
- Institut für Angewandte Physik, Technische Universität Dresden, Dresden, 0 1187, Germany
- Dresden-Würzburg Cluster of Excellence-EXC 2147 (ct.qmat), Dresden, 0 1062, Germany
- Institute of Radiation Physics, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, 0 1328, Germany
| | - Tobias Nörenberg
- Institut für Angewandte Physik, Technische Universität Dresden, Dresden, 0 1187, Germany
- Dresden-Würzburg Cluster of Excellence-EXC 2147 (ct.qmat), Dresden, 0 1062, Germany
| | - Gonzalo Álvarez-Pérez
- Department of Physics, University of Oviedo, Oviedo, 33 006, Spain
- Center of Research on Nanomaterials and Nanotechnology, CINN (CSIC-Universidad de Oviedo), El Entrego, 33 940, Spain
| | - Lukas Wehmeier
- Institut für Angewandte Physik, Technische Universität Dresden, Dresden, 0 1187, Germany
| | - Javier Taboada-Gutiérrez
- Department of Physics, University of Oviedo, Oviedo, 33 006, Spain
- Center of Research on Nanomaterials and Nanotechnology, CINN (CSIC-Universidad de Oviedo), El Entrego, 33 940, Spain
| | - Maximilian Obst
- Institut für Angewandte Physik, Technische Universität Dresden, Dresden, 0 1187, Germany
| | - Franz Hempel
- Institut für Angewandte Physik, Technische Universität Dresden, Dresden, 0 1187, Germany
| | - Eduardo J H Lee
- Departamento de Física de la Materia Condensada, Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid, 28 049, Spain
| | - J Michael Klopf
- Institute of Radiation Physics, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, 0 1328, Germany
| | - Ion Errea
- Fisika Aplikatua 1 Saila, University of the Basque Country (UPV/EHU), Donostia/San Sebastián, 20 018, Spain
- Centro de Física de Materiales (CSIC-UPV/EHU), Donostia/San Sebastián, 20 018, Spain
- Donostia International Physics Center (DIPC), Donostia/San Sebastián, 20 018, Spain
| | - Alexey Y Nikitin
- Donostia International Physics Center (DIPC), Donostia/San Sebastián, 20 018, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, 48013, Spain
| | - Susanne C Kehr
- Institut für Angewandte Physik, Technische Universität Dresden, Dresden, 0 1187, Germany
| | - Pablo Alonso-González
- Department of Physics, University of Oviedo, Oviedo, 33 006, Spain
- Center of Research on Nanomaterials and Nanotechnology, CINN (CSIC-Universidad de Oviedo), El Entrego, 33 940, Spain
| | - Lukas M Eng
- Institut für Angewandte Physik, Technische Universität Dresden, Dresden, 0 1187, Germany
- Dresden-Würzburg Cluster of Excellence-EXC 2147 (ct.qmat), Dresden, 0 1062, Germany
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17
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Bianco R, Monacelli L, Calandra M, Mauri F, Errea I. Weak Dimensionality Dependence and Dominant Role of Ionic Fluctuations in the Charge-Density-Wave Transition of NbSe_{2}. Phys Rev Lett 2020; 125:106101. [PMID: 32955304 DOI: 10.1103/physrevlett.125.106101] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 07/30/2020] [Indexed: 06/11/2023]
Abstract
Contradictory experiments have been reported about the dimensionality effect on the charge-density-wave transition in 2H NbSe_{2}. While scanning tunneling experiments on single layers grown by molecular beam epitaxy measure a charge-density-wave transition temperature in the monolayer similar to the bulk, around 33 K, Raman experiments on exfoliated samples observe a large enhancement of the transition temperature up to 145 K. By employing a nonperturbative approach to deal with anharmonicity, we calculate from first principles the temperature dependence of the phonon spectra both for bulk and monolayer. In both cases, the charge-density-wave transition temperature is estimated as the temperature at which the phonon energy of the mode driving the structural instability vanishes. The obtained transition temperature in the bulk is around 59 K, in rather good agreement with experiments, and it is just slightly increased in the single-layer limit to 73 K, showing the weak dependence of the transition on dimensionality. Environmental factors could motivate the disagreement between the transition temperatures reported by experiments. Our analysis also demonstrates the predominance of ionic fluctuations over electronic ones in the melting of the charge-density-wave order.
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Affiliation(s)
- Raffaello Bianco
- Centro de Física de Materiales (CSIC-UPV/EHU), Manuel de Lardizabal pasealekua 5, 20018 Donostia/San Sebastián, Spain
| | - Lorenzo Monacelli
- Dipartimento di Fisica, Università di Roma Sapienza, Piazzale Aldo Moro 5, I-00185 Roma, Italy
- Graphene Labs, Fondazione Istituto Italiano di Tecnologia, Via Morego, I-16163 Genova, Italy
| | - Matteo Calandra
- Graphene Labs, Fondazione Istituto Italiano di Tecnologia, Via Morego, I-16163 Genova, Italy
- Dipartimento di Fisica, Università di Trento, Via Sommarive 14, 38123 Povo, Italy
- Sorbonne Université, CNRS, Institut des Nanosciences de Paris, UMR7588, F-75252 Paris, France
| | - Francesco Mauri
- Dipartimento di Fisica, Università di Roma Sapienza, Piazzale Aldo Moro 5, I-00185 Roma, Italy
- Graphene Labs, Fondazione Istituto Italiano di Tecnologia, Via Morego, I-16163 Genova, Italy
| | - Ion Errea
- Centro de Física de Materiales (CSIC-UPV/EHU), Manuel de Lardizabal pasealekua 5, 20018 Donostia/San Sebastián, Spain
- Fisika Aplikatua 1 Saila, Gipuzkoako Ingeniaritza Eskola, University of the Basque Country (UPV/EHU), Europa Plaza 1, 20018 Donostia/San Sebastián, Spain
- Donostia International Physics Center (DIPC), Manuel Lardizabal pasealekua 4, 20018 Donostia/San Sebastián, Spain
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18
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Taboada-Gutiérrez J, Álvarez-Pérez G, Duan J, Ma W, Crowley K, Prieto I, Bylinkin A, Autore M, Volkova H, Kimura K, Kimura T, Berger MH, Li S, Bao Q, Gao XPA, Errea I, Nikitin AY, Hillenbrand R, Martín-Sánchez J, Alonso-González P. Broad spectral tuning of ultra-low-loss polaritons in a van der Waals crystal by intercalation. Nat Mater 2020; 19:964-968. [PMID: 32284598 DOI: 10.1038/s41563-020-0665-0] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 03/06/2020] [Indexed: 05/11/2023]
Abstract
Phonon polaritons-light coupled to lattice vibrations-in polar van der Waals crystals are promising candidates for controlling the flow of energy on the nanoscale due to their strong field confinement, anisotropic propagation and ultra-long lifetime in the picosecond range1-5. However, the lack of tunability of their narrow and material-specific spectral range-the Reststrahlen band-severely limits their technological implementation. Here, we demonstrate that intercalation of Na atoms in the van der Waals semiconductor α-V2O5 enables a broad spectral shift of Reststrahlen bands, and that the phonon polaritons excited show ultra-low losses (lifetime of 4 ± 1 ps), similar to phonon polaritons in a non-intercalated crystal (lifetime of 6 ± 1 ps). We expect our intercalation method to be applicable to other van der Waals crystals, opening the door for the use of phonon polaritons in broad spectral bands in the mid-infrared domain.
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Affiliation(s)
- Javier Taboada-Gutiérrez
- Departamento de Física, Universidad de Oviedo, Oviedo, Spain
- Nanomaterials and Nanotechnology Research Center (CINN-CSIC), El Entrego, Spain
| | - Gonzalo Álvarez-Pérez
- Departamento de Física, Universidad de Oviedo, Oviedo, Spain
- Nanomaterials and Nanotechnology Research Center (CINN-CSIC), El Entrego, Spain
| | - Jiahua Duan
- Departamento de Física, Universidad de Oviedo, Oviedo, Spain
- Nanomaterials and Nanotechnology Research Center (CINN-CSIC), El Entrego, Spain
| | - Weiliang Ma
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, China
| | - Kyle Crowley
- Department of Physics, Case Western Reserve University, Cleveland, OH, USA
| | - Iván Prieto
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Andrei Bylinkin
- Donostia International Physics Center (DIPC), Donostia/San Sebastián, Spain
- CIC nanoGUNE BRTA and Department of Electricity and Electronics, UPV/EHU, Donostia/San Sebastián, Spain
| | - Marta Autore
- CIC nanoGUNE BRTA and Department of Electricity and Electronics, UPV/EHU, Donostia/San Sebastián, Spain
| | - Halyna Volkova
- Centre des Matériaux, CNRS UMR 7633-PSL University, MINES ParisTech, Evry Cedex, France
| | - Kenta Kimura
- Department of Advanced Materials Science, University of Tokyo, Kashiwa, Japan
| | - Tsuyoshi Kimura
- Department of Advanced Materials Science, University of Tokyo, Kashiwa, Japan
| | - M-H Berger
- Centre des Matériaux, CNRS UMR 7633-PSL University, MINES ParisTech, Evry Cedex, France
| | - Shaojuan Li
- State Key Laboratory of Applied Optics, Changchun Institute of Optics Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, Jilin, China
| | - Qiaoliang Bao
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, China
- State Key Laboratory of Applied Optics, Changchun Institute of Optics Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, Jilin, China
| | - Xuan P A Gao
- Department of Physics, Case Western Reserve University, Cleveland, OH, USA
| | - Ion Errea
- Donostia International Physics Center (DIPC), Donostia/San Sebastián, Spain
- Fisika Aplikatua 1 Saila, University of the Basque Country (UPV/EHU), Donostia/San Sebastián, Spain
- Centro de Física de Materiales (CSIC-UPV/EHU), Donostia/San Sebastián, Spain
| | - Alexey Y Nikitin
- Donostia International Physics Center (DIPC), Donostia/San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - Rainer Hillenbrand
- CIC nanoGUNE BRTA and Department of Electricity and Electronics, UPV/EHU, Donostia/San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - Javier Martín-Sánchez
- Departamento de Física, Universidad de Oviedo, Oviedo, Spain.
- Nanomaterials and Nanotechnology Research Center (CINN-CSIC), El Entrego, Spain.
| | - Pablo Alonso-González
- Departamento de Física, Universidad de Oviedo, Oviedo, Spain.
- Nanomaterials and Nanotechnology Research Center (CINN-CSIC), El Entrego, Spain.
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19
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Zhou JS, Monacelli L, Bianco R, Errea I, Mauri F, Calandra M. Anharmonicity and Doping Melt the Charge Density Wave in Single-Layer TiSe 2. Nano Lett 2020; 20:4809-4815. [PMID: 32496779 DOI: 10.1021/acs.nanolett.0c00597] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Low-dimensional systems with a vanishing band gap and a large electron-hole interaction have been proposed to be unstable toward exciton formation. As the exciton binding energy increases in low dimension, conventional wisdom suggests that excitonic insulators should be more stable in 2D than in 3D. Here we study the effects of the electron-hole interaction and anharmonicity in single-layer TiSe2. We find that, contrary to the bulk case and to the generally accepted picture, in single-layer TiSe2, the electron-hole exchange interaction is much smaller in 2D than in 3D and it has weak effects on phonon spectra. By calculating anharmonic phonon spectra within the stochastic self-consistent harmonic approximation, we obtain TCDW ≈ 440 K for an isolated and undoped single layer and TCDW ≈ 364 K for an electron-doping n = 4.6 × 1013 cm-2, close to the experimental result of 200-280 K on supported samples. Our work demonstrates that anharmonicity and doping melt the charge density wave in single-layer TiSe2.
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Affiliation(s)
- Jianqiang Sky Zhou
- Sorbonne Université, CNRS, Institut des Nanosciences de Paris, UMR7588, F-75252, Paris, France
| | - Lorenzo Monacelli
- Dipartimento di Fisica, Università di Roma Sapienza, Piazzale Aldo Moro 5, I-00185 Roma, Italy
| | - Raffaello Bianco
- Centro de Física de Materiales (CSIC-UPV/EHU), Manuel de Lardizabal pasealekua 5, 20018 Donostia-San Sebastián, Basque Country, Spain
| | - Ion Errea
- Fisika Aplikatua 1 Saila, Gipuzkoako Ingeniaritza Eskola, University of the Basque Country (UPV/EHU), Europa Plaza 1, 20018 Donostia-San Sebastián, Basque Country, Spain
- Centro de Física de Materiales (CSIC-UPV/EHU), Manuel de Lardizabal pasealekua 5, 20018 Donostia-San Sebastián, Basque Country, Spain
- Donostia International Physics Center (DIPC), Manuel de Lardizabal pasealekua 4, 20018 Donostia-San Sebastián, Basque Country, Spain
| | - Francesco Mauri
- Dipartimento di Fisica, Università di Roma La Sapienza, Piazzale Aldo Moro 5, I-00185 Roma, Italy
- Graphene Laboratories, Fondazione Istituto Italiano di Tecnologia, Via Morego, I-16163 Genova, Italy
| | - Matteo Calandra
- Sorbonne Université, CNRS, Institut des Nanosciences de Paris, UMR7588, F-75252, Paris, France
- Department of Physics, University of Trento, Via Sommarive 14, 38123 Povo, Italy
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20
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Álvarez-Pérez G, Folland TG, Errea I, Taboada-Gutiérrez J, Duan J, Martín-Sánchez J, Tresguerres-Mata AIF, Matson JR, Bylinkin A, He M, Ma W, Bao Q, Martín JI, Caldwell JD, Nikitin AY, Alonso-González P. Infrared Permittivity of the Biaxial van der Waals Semiconductor α-MoO 3 from Near- and Far-Field Correlative Studies. Adv Mater 2020; 32:e1908176. [PMID: 32495483 DOI: 10.1002/adma.201908176] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 03/03/2020] [Accepted: 04/26/2020] [Indexed: 05/21/2023]
Abstract
The biaxial van der Waals semiconductor α-phase molybdenum trioxide (α-MoO3 ) has recently received significant attention due to its ability to support highly anisotropic phonon polaritons (PhPs)-infrared (IR) light coupled to lattice vibrations-offering an unprecedented platform for controlling the flow of energy at the nanoscale. However, to fully exploit the extraordinary IR response of this material, an accurate dielectric function is required. Here, the accurate IR dielectric function of α-MoO3 is reported by modeling far-field polarized IR reflectance spectra acquired on a single thick flake of this material. Unique to this work, the far-field model is refined by contrasting the experimental dispersion and damping of PhPs, revealed by polariton interferometry using scattering-type scanning near-field optical microscopy (s-SNOM) on thin flakes of α-MoO3 , with analytical and transfer-matrix calculations, as well as full-wave simulations. Through these correlative efforts, exceptional quantitative agreement is attained to both far- and near-field properties for multiple flakes, thus providing strong verification of the accuracy of this model, while offering a novel approach to extracting dielectric functions of nanomaterials. In addition, by employing density functional theory (DFT), insights into the various vibrational states dictating the dielectric function model and the intriguing optical properties of α-MoO3 are provided.
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Affiliation(s)
- Gonzalo Álvarez-Pérez
- Department of Physics, University of Oviedo, Oviedo, 33006, Spain
- Center of Research on Nanomaterials and Nanotechnology, CINN (CSIC-Universidad de Oviedo), El Entrego, 33940, Spain
| | - Thomas G Folland
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, 37235, USA
| | - Ion Errea
- Fisika Aplikatua 1 Saila, University of the Basque Country (UPV/EHU), Donostia/San Sebastián, 20018, Spain
- Centro de Física de Materiales (CSIC-UPV/EHU), Donostia/San Sebastián, 20018, Spain
- Donostia International Physics Center (DIPC), Donostia/San Sebastián, 20018, Spain
| | - Javier Taboada-Gutiérrez
- Department of Physics, University of Oviedo, Oviedo, 33006, Spain
- Center of Research on Nanomaterials and Nanotechnology, CINN (CSIC-Universidad de Oviedo), El Entrego, 33940, Spain
| | - Jiahua Duan
- Department of Physics, University of Oviedo, Oviedo, 33006, Spain
- Center of Research on Nanomaterials and Nanotechnology, CINN (CSIC-Universidad de Oviedo), El Entrego, 33940, Spain
| | - Javier Martín-Sánchez
- Department of Physics, University of Oviedo, Oviedo, 33006, Spain
- Center of Research on Nanomaterials and Nanotechnology, CINN (CSIC-Universidad de Oviedo), El Entrego, 33940, Spain
| | | | - Joseph R Matson
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, 37235, USA
| | - Andrei Bylinkin
- CIC nanoGUNE, Donostia/San Sebastián, 20018, Spain
- Moscow Institute of Physics and Technology, Dolgoprudny, 141700, Russia
| | - Mingze He
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, 37235, USA
| | - Weiliang Ma
- Department of Materials Science and Engineering and ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), Monash University, Clayton, Victoria, 3800, Australia
| | - Qiaoliang Bao
- Department of Materials Science and Engineering and ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), Monash University, Clayton, Victoria, 3800, Australia
- Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-based Functional Materials and Devices, Soochow University, Suzhou, Jiangsu, 215123, China
| | - José Ignacio Martín
- Department of Physics, University of Oviedo, Oviedo, 33006, Spain
- Center of Research on Nanomaterials and Nanotechnology, CINN (CSIC-Universidad de Oviedo), El Entrego, 33940, Spain
| | - Joshua D Caldwell
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, 37235, USA
| | - Alexey Y Nikitin
- Donostia International Physics Center (DIPC), Donostia/San Sebastián, 20018, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, 48013, Spain
| | - Pablo Alonso-González
- Department of Physics, University of Oviedo, Oviedo, 33006, Spain
- Center of Research on Nanomaterials and Nanotechnology, CINN (CSIC-Universidad de Oviedo), El Entrego, 33940, Spain
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21
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Bianco R, Errea I, Monacelli L, Calandra M, Mauri F. Quantum Enhancement of Charge Density Wave in NbS 2 in the Two-Dimensional Limit. Nano Lett 2019; 19:3098-3103. [PMID: 30932501 DOI: 10.1021/acs.nanolett.9b00504] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
At ambient pressure, bulk 2H-NbS2 displays no charge density wave instability, which is at odds with the isostructural and isoelectronic compounds 2H-NbSe2, 2H-TaS2, and 2H-TaSe2, and in disagreement with harmonic calculations. Contradictory experimental results have been reported in supported single layers, as 1H-NbS2 on Au(111) does not display a charge density wave, whereas 1H-NbS2 on 6H-SiC(0001) endures a 3 × 3 reconstruction. Here, by carrying out quantum anharmonic calculations from first-principles, we evaluate the temperature dependence of phonon spectra in NbS2 bulk and single layer as a function of pressure/strain. For bulk 2H-NbS2, we find excellent agreement with inelastic X-ray spectra and demonstrate the removal of charge ordering due to anharmonicity. In the two-dimensional limit, we find an enhanced tendency toward charge density wave order. Freestanding 1H-NbS2 undergoes a 3 × 3 reconstruction, in agreement with data on 6H-SiC(0001) supported samples. Moreover, as strains smaller than 0.5% in the lattice parameter are enough to completely remove the 3 × 3 superstructure, deposition of 1H-NbS2 on flexible substrates or a small charge transfer via field-effect could lead to devices with dynamical switching on/off of charge order.
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Affiliation(s)
- Raffaello Bianco
- Department of Applied Physics and Materials Science , California Institute of Technology , Pasadena , California 91125 , United States
- Graphene Laboratories , Fondazione Istituto Italiano di Tecnologia , Via Morego , I-16163 Genova , Italy
- Dipartimento di Fisica , Università di Roma La Sapienza , Piazzale Aldo Moro 5 , I-00185 Roma , Italy
| | - Ion Errea
- Fisika Aplikatua 1 Saila, Gipuzkoako Ingeniaritza Eskola , University of the Basque Country (UPV/EHU) , Europa Plaza 1 , 20018 Donostia-San Sebastián , Basque Country, Spain
- Centro de Física de Materiales (CSIC-UPV/EHU) , Manuel de Lardizabal pasealekua 5 , 20018 Donostia-San Sebastián , Basque Country, Spain
- Donostia International Physics Center (DIPC) , Manuel de Lardizabal pasealekua 4 , 20018 Donostia-San Sebastián , Basque Country, Spain
| | - Lorenzo Monacelli
- Dipartimento di Fisica , Università di Roma La Sapienza , Piazzale Aldo Moro 5 , I-00185 Roma , Italy
| | - Matteo Calandra
- Sorbonne Université , CNRS, Institut des Nanosciences de Paris , UMR7588, F-75252 , Paris , France
| | - Francesco Mauri
- Graphene Laboratories , Fondazione Istituto Italiano di Tecnologia , Via Morego , I-16163 Genova , Italy
- Dipartimento di Fisica , Università di Roma La Sapienza , Piazzale Aldo Moro 5 , I-00185 Roma , Italy
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22
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Aseginolaza U, Bianco R, Monacelli L, Paulatto L, Calandra M, Mauri F, Bergara A, Errea I. Phonon Collapse and Second-Order Phase Transition in Thermoelectric SnSe. Phys Rev Lett 2019; 122:075901. [PMID: 30848620 DOI: 10.1103/physrevlett.122.075901] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 11/29/2018] [Indexed: 06/09/2023]
Abstract
Since 2014 the layered semiconductor SnSe in the high-temperature Cmcm phase is known to be the most efficient intrinsic thermoelectric material. Making use of first-principles calculations we show that its vibrational and thermal transport properties are determined by huge nonperturbative anharmonic effects. We show that the transition from the Cmcm phase to the low-symmetry Pnma is a second-order phase transition driven by the collapse of a zone border phonon, whose frequency vanishes at the transition temperature. Our calculations show that the spectral function of the in-plane vibrational modes are strongly anomalous with shoulders and double-peak structures. We calculate the lattice thermal conductivity obtaining good agreement with experiments only when nonperturbative anharmonic scattering is included. Our results suggest that the good thermoelectric efficiency of SnSe is strongly affected by the nonperturbative anharmonicity.
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Affiliation(s)
- Unai Aseginolaza
- Centro de Física de Materiales CFM, CSIC-UPV/EHU, Paseo Manuel de Lardizabal 5, 20018 Donostia, Basque Country, Spain
- Donostia International Physics Center (DIPC), Manuel Lardizabal pasealekua 4, 20018 Donostia, Basque Country, Spain
- Fisika Aplikatua 1 Saila, University of the Basque Country (UPV/EHU), Europa Plaza 1, 20018 Donostia, Basque Country, Spain
| | - Raffaello Bianco
- Dipartimento di Fisica, Università di Roma La Sapienza, Piazzale Aldo Moro 5, I-00185 Roma, Italy
- Graphene Labs, Fondazione Istituto Italiano di Tecnologia, Via Morego, I-16163 Genova, Italy
- Department of Applied Physics and Material Science, Steele Laboratory, California Institute of Technology, Pasadena, California 91125, USA
| | - Lorenzo Monacelli
- Dipartimento di Fisica, Università di Roma La Sapienza, Piazzale Aldo Moro 5, I-00185 Roma, Italy
| | - Lorenzo Paulatto
- IMPMC, UMR CNRS 7590, Sorbonne Universités-UPMC Univ. Paris 06, MNHN, IRD, 4 Place Jussieu, F-75005 Paris, France
| | - Matteo Calandra
- Sorbonne Universités, CNRS, Institut des Nanosciences de Paris, UMR7588, F-75252 Paris, France
| | - Francesco Mauri
- Dipartimento di Fisica, Università di Roma La Sapienza, Piazzale Aldo Moro 5, I-00185 Roma, Italy
- Graphene Labs, Fondazione Istituto Italiano di Tecnologia, Via Morego, I-16163 Genova, Italy
| | - Aitor Bergara
- Centro de Física de Materiales CFM, CSIC-UPV/EHU, Paseo Manuel de Lardizabal 5, 20018 Donostia, Basque Country, Spain
- Donostia International Physics Center (DIPC), Manuel Lardizabal pasealekua 4, 20018 Donostia, Basque Country, Spain
- Departamento de Física de la Materia Condensada, University of the Basque Country (UPV/EHU), 48080 Bilbao, Basque Country, Spain
| | - Ion Errea
- Donostia International Physics Center (DIPC), Manuel Lardizabal pasealekua 4, 20018 Donostia, Basque Country, Spain
- Fisika Aplikatua 1 Saila, University of the Basque Country (UPV/EHU), Europa Plaza 1, 20018 Donostia, Basque Country, Spain
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Borinaga M, Ibañez-Azpiroz J, Bergara A, Errea I. Strong Electron-Phonon and Band Structure Effects in the Optical Properties of High Pressure Metallic Hydrogen. Phys Rev Lett 2018; 120:057402. [PMID: 29481166 DOI: 10.1103/physrevlett.120.057402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Indexed: 06/08/2023]
Abstract
The recent claim of having produced metallic hydrogen in the laboratory relies on measurements of optical spectra. Here, we present first-principles calculations of the reflectivity of hydrogen between 400 and 600 GPa in the I4_{1}/amd crystal structure, the one predicted at these pressures, based on both time-dependent density functional and Eliashberg theories, thus, covering the optical properties from the infrared to the ultraviolet regimes. Our results show that atomic hydrogen displays an interband plasmon at around 6 eV that abruptly suppresses the reflectivity, while the large superconducting gap energy yields a sharp decrease of the reflectivity in the infrared region approximately at 120 meV. The experimentally estimated electronic scattering rates in the 0.7-3 eV range are in agreement with our theoretical estimations, which show that the huge electron-phonon interaction of the system dominates the electronic scattering in this energy range. The remarkable features in the optical spectra predicted here encourage extending the optical measurements to the infrared and ultraviolet regions as our results suggest optical measurements can potentially identify high-pressure phases of hydrogen.
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Affiliation(s)
- Miguel Borinaga
- Centro de Física de Materiales CFM, CSIC-UPV/EHU, Manuel Lardizabal Pasealekua 5, 20018 Donostia/San Sebastián, Basque Country, Spain
- Donostia International Physics Center (DIPC), Manuel Lardizabal Pasealekua 4, 20018 Donostia/San Sebastián, Basque Country, Spain
| | - Julen Ibañez-Azpiroz
- Peter Grünberg Institute and Institute for Advanced Simulation, Forschungszentrum Jülich & JARA, D-52425 Jülich, Germany
| | - Aitor Bergara
- Centro de Física de Materiales CFM, CSIC-UPV/EHU, Manuel Lardizabal Pasealekua 5, 20018 Donostia/San Sebastián, Basque Country, Spain
- Donostia International Physics Center (DIPC), Manuel Lardizabal Pasealekua 4, 20018 Donostia/San Sebastián, Basque Country, Spain
- Departamento de Física de la Materia Condensada, University of the Basque Country (UPV/EHU), 48080 Bilbao, Basque Country, Spain
| | - Ion Errea
- Donostia International Physics Center (DIPC), Manuel Lardizabal Pasealekua 4, 20018 Donostia/San Sebastián, Basque Country, Spain
- Fisika Aplikatua 1 Saila, Bilboko Ingeniaritza Eskola, University of the Basque Country (UPV/EHU), Rafael Moreno "Pitxitxi" Pasealekua 3, 48013 Bilbao, Basque Country, Spain
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Nemausat R, Gervais C, Brouder C, Trcera N, Bordage A, Coelho-Diogo C, Florian P, Rakhmatullin A, Errea I, Paulatto L, Lazzeri M, Cabaret D. Temperature dependence of X-ray absorption and nuclear magnetic resonance spectra: probing quantum vibrations of light elements in oxides. Phys Chem Chem Phys 2017; 19:6246-6256. [DOI: 10.1039/c6cp08393e] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Probing the quantum thermal fluctuations of nuclei in light-element oxides using XANES and NMR spectroscopies.
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Affiliation(s)
- Ruidy Nemausat
- Sorbonne Universités
- UPMC Univ Paris 06
- IMPMC
- UMR CNRS 7590
- F-75005 Paris
| | - Christel Gervais
- Sorbonne Universités
- UPMC Univ Paris 06
- LCMCP
- Collège de France
- UMR CNRS 7574
| | - Christian Brouder
- Sorbonne Universités
- UPMC Univ Paris 06
- IMPMC
- UMR CNRS 7590
- F-75005 Paris
| | - Nicolas Trcera
- Synchrotron SOLEIL
- L'Orme des Merisiers
- F-91192 Gif sur Yvette
- France
| | - Amélie Bordage
- ICMMO
- Univ Paris Sud
- Univ Paris-Saclay
- UMR CNRS 8182
- F-91405 Orsay
| | | | | | | | - Ion Errea
- Fisika Aplikatua 1 Saila
- Bilboko Ingeniaritza Eskola
- University of the Basque Country (UPV/EHU)
- 48013 Bilbao
- Spain
| | - Lorenzo Paulatto
- Sorbonne Universités
- UPMC Univ Paris 06
- IMPMC
- UMR CNRS 7590
- F-75005 Paris
| | - Michele Lazzeri
- Sorbonne Universités
- UPMC Univ Paris 06
- IMPMC
- UMR CNRS 7590
- F-75005 Paris
| | - Delphine Cabaret
- Sorbonne Universités
- UPMC Univ Paris 06
- IMPMC
- UMR CNRS 7590
- F-75005 Paris
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Borinaga M, Riego P, Leonardo A, Calandra M, Mauri F, Bergara A, Errea I. Anharmonic enhancement of superconductivity in metallic molecular Cmca - 4 hydrogen at high pressure: a first-principles study. J Phys Condens Matter 2016; 28:494001. [PMID: 27713189 DOI: 10.1088/0953-8984/28/49/494001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
First-principles calculations based on density-functional theory including anharmonicity within the variational stochastic self-consistent harmonic approximation are applied to understand how the quantum character of the proton affects the candidate metallic molecular Cmca - 4 structure of hydrogen in the 400-450 GPa pressure range, where metallization of hydrogen is expected to occur. Anharmonic effects, which become crucial due to the zero-point motion, have a large impact on the hydrogen molecules by increasing the intramolecular distance by approximately a 6%. This induces two new electron pockets at the Fermi surface opening new scattering channels for the electron-phonon interaction. Consequently, the electron-phonon coupling constant and the superconducting critical temperature are approximately doubled by anharmonicity and Cmca - 4 hydrogen becomes a superconductor above 200 K in all the studied pressure range. Contrary to many superconducting hydrides, where anharmoncity tends to lower the superconducting critical temperature, our results show that it can enhance superconductivity in molecular hydrogen.
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Affiliation(s)
- Miguel Borinaga
- Centro de Física de Materiales CFM, CSIC-UPV/EHU, Paseo Manuel de Lardizabal 5, 20018 Donostia/San Sebastián, Basque Country, Spain. Donostia International Physics Center (DIPC), Manuel Lardizabal pasealekua 4, 20018 Donostia/San Sebastián, Basque Country, Spain
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Errea I, Calandra M, Pickard CJ, Nelson J, Needs RJ, Li Y, Liu H, Zhang Y, Ma Y, Mauri F. High-pressure hydrogen sulfide from first principles: a strongly anharmonic phonon-mediated superconductor. Phys Rev Lett 2015; 114:157004. [PMID: 25933334 DOI: 10.1103/physrevlett.114.157004] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Indexed: 06/04/2023]
Abstract
We use first-principles calculations to study structural, vibrational, and superconducting properties of H_{2}S at pressures P≥200 GPa. The inclusion of zero-point energy leads to two different possible dissociations of H2S, namely 3H2S→2H3S+S and 5H2S→3H3S+HS2, where both H3S and HS2 are metallic. For H3S, we perform nonperturbative calculations of anharmonic effects within the self-consistent harmonic approximation and show that the harmonic approximation strongly overestimates the electron-phonon interaction (λ≈2.64 at 200 GPa) and Tc. Anharmonicity hardens H─S bond-stretching modes and softens H─S bond-bending modes. As a result, the electron-phonon coupling is suppressed by 30% (λ≈1.84 at 200 GPa). Moreover, while at the harmonic level Tc decreases with increasing pressure, the inclusion of anharmonicity leads to a Tc that is almost independent of pressure. High-pressure hydrogen sulfide is a strongly anharmonic superconductor.
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Affiliation(s)
- Ion Errea
- Donostia International Physics Center (DIPC), Manuel de Lardizabal Pasealekua 4, 20018 Donostia-San Sebastián, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - Matteo Calandra
- IMPMC, UMR CNRS 7590, Sorbonne Universités-UPMC University Paris 06, MNHN, IRD, 4 Place Jussieu, F-75005 Paris, France
| | - Chris J Pickard
- Department of Physics & Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Joseph Nelson
- Theory of Condensed Matter Group, Cavendish Laboratory, J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Richard J Needs
- Theory of Condensed Matter Group, Cavendish Laboratory, J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Yinwei Li
- School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116, People's Republic of China
| | - Hanyu Liu
- Department of Physics and Engineering Physics, University of Saskatchewan, Saskatchewan S7N 5E2, Canada
| | - Yunwei Zhang
- State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, People's Republic of China
| | - Yanming Ma
- State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, People's Republic of China
| | - Francesco Mauri
- IMPMC, UMR CNRS 7590, Sorbonne Universités-UPMC University Paris 06, MNHN, IRD, 4 Place Jussieu, F-75005 Paris, France
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Errea I, Calandra M, Mauri F. First-principles theory of anharmonicity and the inverse isotope effect in superconducting palladium-hydride compounds. Phys Rev Lett 2013; 111:177002. [PMID: 24206514 DOI: 10.1103/physrevlett.111.177002] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Indexed: 06/02/2023]
Abstract
Palladium hydrides display the largest isotope effect anomaly known in the literature. Replacement of hydrogen with the heavier isotopes leads to higher superconducting temperatures, a behavior inconsistent with harmonic theory. Solving the self-consistent harmonic approximation by a stochastic approach, we obtain the anharmonic free energy, the thermal expansion, and the superconducting properties fully ab initio. We find that the phonon spectra are strongly renormalized by anharmonicity far beyond the perturbative regime. Superconductivity is phonon mediated, but the harmonic approximation largely overestimates the superconducting critical temperatures. We explain the inverse isotope effect, obtaining a -0.38 value for the isotope coefficient in good agreement with experiments, hydrogen anharmonicity being mainly responsible for the isotope anomaly.
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Affiliation(s)
- Ion Errea
- Université Pierre et Marie Curie, CNRS, IMPMC, 4 Place Jussieu, 75252 Paris, France and IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain
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Errea I, Rousseau B, Bergara A. Anharmonic stabilization of the high-pressure simple cubic phase of calcium. Phys Rev Lett 2011; 106:165501. [PMID: 21599380 DOI: 10.1103/physrevlett.106.165501] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Revised: 03/24/2011] [Indexed: 05/30/2023]
Abstract
The phonon spectrum of the high-pressure simple cubic phase of calcium, in the harmonic approximation, shows imaginary branches that make it mechanically unstable. In this Letter, the phonon spectrum is recalculated by using density-functional theory ab initio methods fully including anharmonic effects up to fourth order at 50 GPa. Considering that the perturbation theory cannot be employed with imaginary harmonic frequencies, a variational procedure based on the Gibbs-Bogoliubov inequality is used to estimate the renormalized phonon frequencies. The results show that strong quantum anharmonic effects make the imaginary phonons become positive even at zero temperature so that the simple cubic phase becomes mechanically stable, as experiments suggest. Moreover, our calculations find a superconducting T(c) in agreement with experiments and predict an anomalous behavior of the specific heat.
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Affiliation(s)
- Ion Errea
- Materia Kondentsatuaren Fisika Saila, Zientzia eta Teknologia Fakultatea, Euskal Herriko Unibertsitatea, Bilbao, Basque Country, Spain
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Abstract
Experimental studies established that calcium undergoes several counterintuitive transitions under pressure: fcc --> bcc --> simple cubic --> Ca-IV --> Ca-V, and becomes a good superconductor in the simple cubic and higher-pressure phases. Here, using ab initio evolutionary simulations, we explore the behavior of Ca under pressure and find a number of new phases. Our structural sequence differs from the traditional picture for Ca, but is similar to that for Sr. The beta-tin (I4(1)/amd) structure, rather than simple cubic, is predicted to be the theoretical ground state at 0 K and 33-71 GPa. This structure can be represented as a large distortion of the simple cubic structure, just as the higher-pressure phases stable between 71 and 134 GPa. The structure of Ca-V, stable above 134 GPa, is a complex host-guest structure. According to our calculations, the predicted phases are superconductors with Tc increasing under pressure and reaching approximately 20 K at 120 GPa, in good agreement with experiment.
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Affiliation(s)
- Artem R. Oganov
- Department of Geosciences, Department of Physics and Astronomy, and New York Center for Computational Sciences, Stony Brook University, Stony Brook, NY 11794-2100
- Geology Department, Moscow State University, 119992 Moscow, Russia
| | - Yanming Ma
- National Lab of Superhard Materials, Jilin University, Changchun 130012, China
| | - Ying Xu
- National Lab of Superhard Materials, Jilin University, Changchun 130012, China
| | - Ion Errea
- Materia Kondentsatuaren Fisika Saila, Zientzia eta Teknologia Fakultatea, Euskal Herriko Unibertsitatea, 644 Postakutxatila, 48080 Bilbao, Basque Country, Spain
- Donostia International Physics Center, Paseo de Manuel Lardizabal, 20018 Donostia, Basque Country, Spain; and
| | - Aitor Bergara
- Materia Kondentsatuaren Fisika Saila, Zientzia eta Teknologia Fakultatea, Euskal Herriko Unibertsitatea, 644 Postakutxatila, 48080 Bilbao, Basque Country, Spain
- Donostia International Physics Center, Paseo de Manuel Lardizabal, 20018 Donostia, Basque Country, Spain; and
- Centro Fisica de Materiales, Spanish Scientific Research Council (CSIC) and the University of the Basque Country (UPV/EHU), 1072 Posta kutxatila, E-20080 Donostia, Basque Country, Spain
| | - Andriy O. Lyakhov
- Department of Geosciences, Department of Physics and Astronomy, and New York Center for Computational Sciences, Stony Brook University, Stony Brook, NY 11794-2100
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