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Liu Y, Cui T, Li D. Emerging d- d orbital coupling between non- d-block main-group elements Mg and I at high pressure. iScience 2023; 26:106113. [PMID: 36879798 PMCID: PMC9984552 DOI: 10.1016/j.isci.2023.106113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 11/30/2022] [Accepted: 01/28/2023] [Indexed: 02/05/2023] Open
Abstract
d-d orbital coupling, which increases anisotropic and directional bonding, commonly occurs between d-block transition metals. Here, we report an unexpected d-d orbital coupling in the non-d-block main-group element compound Mg2I based on first-principles calculations. The unfilled d orbitals of Mg and I atoms under ambient conditions become part of the valence orbitals and couple with each other under high pressures, resulting in the formation of highly symmetric I-Mg-I covalent bonding in Mg2I, which forces the valence electrons of Mg atoms into the lattice voids to form interstitial quasi-atoms (ISQs). In turn, the ISQs highly interact with the crystal lattice, contributing to lattice stability. This study greatly enriches the fundamental understanding of chemical bonding between non-d-block main-group elements at high pressures.
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Affiliation(s)
- Yan Liu
- State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, P.R. China
| | - Tian Cui
- State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, P.R. China.,School of Physical Science and Technology, Ningbo University, Ningbo 315211, P.R. China
| | - Da Li
- State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, P.R. China
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2
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Machon D, Le Floch S, Mishra S, Daniele S, Masenelli-Varlot K, Hermet P, Mélinon P. Extreme structural stability of Ti 0.5Sn 0.5O 2 nanoparticles: synergistic effect in the cationic sublattice. NANOSCALE 2022; 14:14286-14296. [PMID: 36134596 DOI: 10.1039/d2nr03441g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Ti0.5Sn0.5O2 nanoparticles (∼5 nm and ∼10 nm) have been studied under high pressure by Raman spectroscopy. For particles with diameter ∼10 nm, a transformation has been observed at 20-25 GPa while for particles with ∼5 nm diameter no phase transition has been observed up to ∼30 GPa. The Ti0.5Sn0.5O2 solid solution shows an extended stability at the nanoscale, both of its cationic and anionic sublattices. This ultrastability originates from the contribution of Ti and Sn mixing: Sn stabilizes the cationic network at high pressure and Ti ensures a coupling between the cationic and anionic sublattices. This result questions a "traditional" crystallographic description based on polyhedra packing and this synergistic effect reported in this work is similar to the case of metamaterials but at the nanoscale.
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Affiliation(s)
- Denis Machon
- Univ. Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5306, Institut Lumière Matière, F-69622 Villeurbanne, France.
- Laboratoire Nanotechnologies et Nanosystèmes (LN2), CNRS UMI-3463, Université de Sherbrooke, Institut Interdisciplinaire d'Innovation Technologique(3IT), Sherbrooke, Québec, Canada
| | - Sylvie Le Floch
- Univ. Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5306, Institut Lumière Matière, F-69622 Villeurbanne, France.
| | - Shashank Mishra
- IRCELYON, CNRS-UMR 5256, Université Lyon 1, 2 Avenue A. Einstein, 69626 Villeurbanne Cedex, France
| | - Stéphane Daniele
- IRCELYON, CNRS-UMR 5256, Université Lyon 1, 2 Avenue A. Einstein, 69626 Villeurbanne Cedex, France
| | | | - Patrick Hermet
- ICGM, CNRS-UMR 5253, Université de Montpellier, ENSCM, 34090 Montpellier, France
| | - Patrice Mélinon
- Univ. Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5306, Institut Lumière Matière, F-69622 Villeurbanne, France.
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3
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Zhu SC, Huang ZB, Hu Q, Xu L. Pressure tuned incommensurability and guest structure transition in compressed scandium from machine learning atomic simulation. Phys Chem Chem Phys 2022; 24:7007-7013. [PMID: 35254347 DOI: 10.1039/d1cp05803g] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Scandium (Sc) is the lightest non-main-group element and transforms to a host-guest (H-G) incommensurate structure under gigapascal (GPa) pressures. While the host structure is stable over a wide pressure range, the guest structure may exist in multiple forms, featuring different incommensurate ratios, and mixing up to generate long-range "disordered" guest structures. Here, we employed the recently developed global neural network (g-NN) potential and the stochastic surface walking (SSW) global optimization algorithm to explore the global potential energy surface of Sc under various pressures. We probe the global minima structure in a system made of hundreds of atoms and revealed that the solid-phase transition between Sc-I and H-G Sc-II phases is fully reconstructive in nature. Above 62.5 GPa, the pressure will further destabilize the face-centered tetragonal (fct, Sc-IIa) guest structure to a body-centered tetragonal phase (bct, Sc-IIb), while sustaining the host structure. The structural transition mechanism of this work will shed light on the nature of the complex H-G structural modifications in compressed metals.
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Affiliation(s)
- Sheng-Cai Zhu
- School of Materials, Shenzhen Campus of Sun Yat-sen University, Shenzhen 518107, China.
| | - Zhen-Bo Huang
- School of Materials, Shenzhen Campus of Sun Yat-sen University, Shenzhen 518107, China.
| | - Qingyang Hu
- Center for High Pressure Science and Technology Advanced Research, Beijing 100094, P. R. China.,CAS Center for Excellence in Deep Earth Science, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, P. R. China
| | - Liang Xu
- National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900, China
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4
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Crystal Structure Prediction and Lattice Dynamical Calculations for the Rare Platinum-Group Mineral Zaccariniite (RhNiAs). MINERALS 2022. [DOI: 10.3390/min12010098] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The crystal structures of newly found minerals are routinely determined using single-crystal techniques. However, many rare minerals usually form micrometer-sized aggregates that are difficult to study with conventional structural methods. This is the case for numerous platinum-group minerals (PGMs) such as, for instance, zaccariniite (RhNiAs), the crystal structure of which was first obtained by studying synthetic samples. The aim of the present work is to explore the usefulness of USPEX, a powerful crystal structure prediction method, as an alternative means of determining the crystal structure of minerals such as zaccariniite, with a relatively simple crystal structure and chemical formula. We show that fixed composition USPEX searches with a variable number of formula units, using the ideal formula of the mineral as the only starting point, successfully predict the tetragonal structure of a mineral. Density functional theory (DFT) calculations can then be performed in order to more tightly relax the structure of the mineral and calculate different fundamental properties, such as the frequency of zone-center Raman-active phonons, or even their pressure behavior. These theoretical data can be subsequently compared to experimental results, which, in the case of newly found minerals, would allow one to confirm the correctness of the crystal structure predicted by the USPEX code.
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5
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Li C, Li W, Zhang X, Du L, Sheng HW. Predicted Stable Electrides in Mg-Al System under High Pressure. Phys Chem Chem Phys 2022; 24:12260-12266. [DOI: 10.1039/d2cp00981a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Magnesium and aluminum, as the adjacent light metal elements, are difficult to form the stable stoichiometries compounds under ambient conditions. In this work, using evolutionary ab initio structural prediction approaches,...
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6
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Anzellini S, Alfé D, Pozzo M, Errandonea D. Melting line of calcium characterized by in situ LH-DAC XRD and first-principles calculations. Sci Rep 2021; 11:15025. [PMID: 34294781 PMCID: PMC8298416 DOI: 10.1038/s41598-021-94349-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 07/09/2021] [Indexed: 11/16/2022] Open
Abstract
In this work, the melting line of calcium has been characterized both experimentally, using synchrotron X-ray diffraction in laser-heated diamond-anvil cells, and theoretically, using first-principles calculations. In the investigated pressure and temperature range (pressure between 10 and 40 GPa and temperature between 300 and 3000 K) it was possible to observe the face-centred phase of calcium and to confirm (and characterize for the first time at these conditions) the presence of the body-centred cubic and the simple cubic phase of calcium. The melting points obtained with the two techniques are in excellent agreement. Furthermore, the present results agree with the only existing melting line of calcium obtained in laser-heated diamond anvil cells, using the speckle method as melting detection technique. They also confirm a flat slope of the melting line in the pressure range between 10 and 30 GPa. The flat melting curve is associated with the presence of the solid high-temperature body-centered cubic phase of calcium and to a small volume change between this phase and the liquid at melting. Reasons for the stabilization of the body-centered face at high-temperature conditions will be discussed.
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Affiliation(s)
- Simone Anzellini
- Diamond Light Source Ltd., Harwell Science & Innovation Campus, Diamond House, Didcot, OX11 0DE, UK.
| | - Dario Alfé
- Dipartimento di Fisica Ettore Pancini, Università di Napoli Federico II, Monte S. Angelo, 80126, Napoli, Italy.,Department of Earth Sciences and London Centre for Nanotechnology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Monica Pozzo
- Department of Earth Sciences and London Centre for Nanotechnology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Daniel Errandonea
- Departamento de Física Aplicada - Instituto de Ciencia de Materiales, Matter at High Pressure (MALTA) Consolider Team, Universidad de Valencia, Edificio de Investigación, C/Dr. Moliner 50, Burjassot, Valencia, 46100, Spain
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7
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Yu H, Chen Y. Pressure-induced electrides and metallic phases in the Y-Cl system. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:215401. [PMID: 33578406 DOI: 10.1088/1361-648x/abe607] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 02/12/2021] [Indexed: 06/12/2023]
Abstract
Pressure can profoundly change the electronic structure, leading to the formation of new phases and materials with exotic properties. Herein, using evolutionary algorithms and density functional theory, we systematically investigate the behaviour of materials in the yttrium-chlorine binary system under pressure. Electrons are found to be spatially confined at low pressures in yttrium chlorides and tend to form new electrides. In particular, a novel yttrium chloride, Y3Cl2, is predicted to be thermodynamically and lattice dynamically stable at approximately 10 GPa. Further analyses of the electron localization function and partial charge density identify trigonal Y3Cl2as a new 2D high-pressure electride with partially localized electrons contributing to the conduction. By further increasing the pressure, electrons in the yttrium-chlorine binary system tend to delocalize with the electrides decomposing into two new compounds (Y2Cl and YCl2) and a new YCl phase (space groupP63/mmc) above 20 GPa. These newly discovered phases are all metallic in their stable pressure range according to band structure simulations without interstitial electron localization. The discovery of these unconventional yttrium chlorides may inspire strategies to search for low-pressure electrides in other rare-earth halogenide systems.
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Affiliation(s)
- Hulei Yu
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, People's Republic of China
| | - Yue Chen
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, People's Republic of China
- HKU Zhejiang Institute of Research and Innovation, 1623 Dayuan Road, Lin An 311305, People's Republic of China
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8
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Novoselov DY, Korotin DM, Shorikov AO, Oganov AR, Anisimov VI. Weak Coulomb correlations stabilize the electride high-pressure phase of elemental calcium. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:445501. [PMID: 32503018 DOI: 10.1088/1361-648x/ab99ed] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 06/05/2020] [Indexed: 06/11/2023]
Abstract
Theoretical studies using the state-of-the-art density functional theory and dynamicalmean-field theory (DFT + DMFT) method show that weak electronic correlation effects are crucial for reproducing the experimentally observed pressure-induced phase transitions of calcium from β-tin toCmmmand then to the simple cubic structure. The formation of an electride state in calcium leads to the emergence of partially filled and localized electronic states under compression. The electride state was described using a basis containing molecular orbitals centered on the interstitial site and Ca-d states. We investigate the influence of Coulomb correlations on the structural properties of elemental Ca, noting that approaches based on the Hartree-Fock method (DFT +Uor hybrid functional schemes) are poorly suited for describing correlated metals. We find that only the DFT + DMFT method reproduces the correct sequence of high-pressure phase transitions of Ca at low temperatures.
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Affiliation(s)
- Dmitry Y Novoselov
- M.N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences-620108, Yekaterinburg, Russia
- Department of Theoretical Physics and Applied Mathematics, Ural Federal University, Mira St. 19, 620002 Yekaterinburg, Russia
- Skolkovo Institute of Science and Technology, 3 Nobel St., Moscow, 143026, Russia
| | - Dmitry M Korotin
- M.N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences-620108, Yekaterinburg, Russia
- Skolkovo Institute of Science and Technology, 3 Nobel St., Moscow, 143026, Russia
| | - Alexey O Shorikov
- M.N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences-620108, Yekaterinburg, Russia
- Department of Theoretical Physics and Applied Mathematics, Ural Federal University, Mira St. 19, 620002 Yekaterinburg, Russia
- Skolkovo Institute of Science and Technology, 3 Nobel St., Moscow, 143026, Russia
| | - Artem R Oganov
- Skolkovo Institute of Science and Technology, 3 Nobel St., Moscow, 143026, Russia
- Moscow Institute of Physics and Technology, 9 Institutskiy per., Dolgoprudny, Moscow Region, 141701, Russia
| | - Vladimir I Anisimov
- M.N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences-620108, Yekaterinburg, Russia
- Department of Theoretical Physics and Applied Mathematics, Ural Federal University, Mira St. 19, 620002 Yekaterinburg, Russia
- Skolkovo Institute of Science and Technology, 3 Nobel St., Moscow, 143026, Russia
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9
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Paul R, Hu SX, Karasiev VV. Anharmonic and Anomalous Trends in the High-Pressure Phase Diagram of Silicon. PHYSICAL REVIEW LETTERS 2019; 122:125701. [PMID: 30978067 DOI: 10.1103/physrevlett.122.125701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Indexed: 06/09/2023]
Abstract
A multifaceted first-principles approach utilizing density functional theory, evolutionary algorithms, and lattice dynamics was used to construct the phase diagram of silicon up to 4 TPa and 26 000 K. These calculations predicted that (i) an anomalous sequence of face-centered cubic to body-centered cubic to simple cubic crystalline phase transitions occur at pressures of 2.87 and 3.89 TPa, respectively, along the cold curve, (ii) the orthorhombic phases of Imma and Cmce-16 appear on the phase diagram only when the anharmonic contribution to the Gibbs free energy is taken into account, and (iii) a substantial change in the slope of the principal Hugoniot is observed if the anharmonic free energy of the cubic diamond phase is considered.
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Affiliation(s)
- R Paul
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - S X Hu
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - V V Karasiev
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
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10
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Zhao Z, Zhang S, Yu T, Xu H, Bergara A, Yang G. Predicted Pressure-Induced Superconducting Transition in Electride Li_{6}P. PHYSICAL REVIEW LETTERS 2019; 122:097002. [PMID: 30932540 DOI: 10.1103/physrevlett.122.097002] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Indexed: 06/09/2023]
Abstract
Electrides are unique compounds where most of the electrons reside at interstitial regions of the crystal behaving as anions, which strongly determines its physical properties. Interestingly, the magnitude and distribution of interstitial electrons can be effectively modified either by modulating its chemical composition or external conditions (e.g., pressure). Most of the electrides under high pressure are nonmetallic, and superconducting electrides are very rare. Here we report that a pressure-induced stable Li_{6}P electride, identified by first-principles swarm structure calculations, becomes a superconductor with a predicted superconducting transition temperature T_{c} of 39.3 K, which is the highest among the already known electrides. The interstitial electrons in Li_{6}P, with dumbbell-like connected electride states, play a dominant role in the superconducting transition. Other Li-rich phosphides, Li_{5}P, Li_{11}P_{2}, Li_{15}P_{2}, and Li_{8}P, are also predicted to be superconducting electrides, but with a lower T_{c}. Superconductivity in all these compounds can be attributed to a combination of a weak electronegativity of phosphorus (P) with a strong electropositivity of lithium (Li), and opens up the interest to explore high-temperature superconductivity in similar binary compounds.
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Affiliation(s)
- Ziyuan Zhao
- Centre for Advanced Optoelectronic Functional Materials Research and Laboratory for UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, China
| | - Shoutao Zhang
- Centre for Advanced Optoelectronic Functional Materials Research and Laboratory for UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, China
| | - Tong Yu
- Centre for Advanced Optoelectronic Functional Materials Research and Laboratory for UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, China
| | - Haiyang Xu
- Centre for Advanced Optoelectronic Functional Materials Research and Laboratory for UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, China
| | - Aitor Bergara
- Departamento de Física de la Materia Condensada, Universidad del País Vasco-Euskal Herriko Unibertsitatea, UPV/EHU, 48080 Bilbao, Spain
- Donostia International Physics Center (DIPC), 20018 Donostia, Spain
- Centro de Física de Materiales CFM, Centro Mixto CSIC-UPV/EHU, 20018 Donostia, Spain
| | - Guochun Yang
- Centre for Advanced Optoelectronic Functional Materials Research and Laboratory for UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, China
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11
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Schwarz U, Kasinathan D, Bergner C, Hunger J, Meier-Kircher K, Akselrud L, Hanfland M, Mezouar M, Glazyrin K, Stinton GW, Husband R, Rosner H, McMahon MI. Distortions in the cubic primitive high-pressure phases of calcium. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:065401. [PMID: 30523800 DOI: 10.1088/1361-648x/aaf49b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The superconductivity in highly compressed calcium involves the occurrence of closely related low-symmetry structural patterns with an exceptionally low coordination number. Earlier theoretical and experimental results are controversial and some findings are inconsistent with our later observations in the pressure range up to 60 GPa. This situation motivated the present concerted computational and experimental re-investigation of the structural arrangement of calcium slightly above the high-pressure limit of the bcc arrangement at low-temperatures. We report here reproducible experimental evidence for a monoclinic distortion (mC4, space group C2/c) of the calcium polymorph previously assigned to the tetragonal β-Sn structure type. In accordance, the enthalpies calculated by electronic band structure calculations show the mC4 phase to be more stable than the undistorted β-Sn type by about 100 meV in the entire phase space. The other low-temperature phase of calcium adopts space group Cmcm (oC4) rather than the earlier assigned Cmmm symmetry. These structural alterations substantially effect the density of states at the Fermi level and, thus, the electronic properties.
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Affiliation(s)
- Ulrich Schwarz
- Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, D-01187 Dresden, Germany
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12
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Ibarra-Hernández W, Hajinazar S, Avendaño-Franco G, Bautista-Hernández A, Kolmogorov AN, Romero AH. Structural search for stable Mg–Ca alloys accelerated with a neural network interatomic model. Phys Chem Chem Phys 2018; 20:27545-27557. [DOI: 10.1039/c8cp05314f] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have combined a neural network formalism with metaheuristic structural global search algorithms to systematically screen the Mg–Ca binary system for new (meta)stable alloys.
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Affiliation(s)
- Wilfredo Ibarra-Hernández
- Facultad de Ingeniería-BUAP
- Apartado Postal J-39
- Mexico
- Department of Physics and Astronomy
- West Virginia University
| | - Samad Hajinazar
- Department of Physics
- Applied Physics and Astronomy
- Binghamton University
- State University of New York
- Binghamton
| | | | | | - Aleksey N. Kolmogorov
- Department of Physics
- Applied Physics and Astronomy
- Binghamton University
- State University of New York
- Binghamton
| | - Aldo H. Romero
- Facultad de Ingeniería-BUAP
- Apartado Postal J-39
- Mexico
- Department of Physics and Astronomy
- West Virginia University
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13
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Zhang Y, Wu W, Wang Y, Yang SA, Ma Y. Pressure-Stabilized Semiconducting Electrides in Alkaline-Earth-Metal Subnitrides. J Am Chem Soc 2017; 139:13798-13803. [DOI: 10.1021/jacs.7b07016] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yunwei Zhang
- State
Key Lab of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China
- Beijing Computational Science Research Center, Beijing 100084, China
- Research
Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Weikang Wu
- Research
Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Yanchao Wang
- State
Key Lab of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China
| | - Shengyuan A. Yang
- Research
Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Yanming Ma
- State
Key Lab of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China
- International
Center of Future Science, Jilin University, Changchun 130012, China
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14
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Sun X, Lei Y, Zhou R, Qu B, Li D, Zhang B, Zeng XC. New phases of 3d-transition metal–cerium binary compounds: an extensive structural search. RSC Adv 2017. [DOI: 10.1039/c7ra07103e] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The phase stabilities, structural features, electronic and mechanical properties of 3d transitional metal–cerium binary compounds were systematically studied.
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Affiliation(s)
- Xiaorui Sun
- Laboratory of Amorphous Matter and Science
- School of Materials Science and Engineering
- Hefei University of Technology
- Hefei
- China
| | - Yawei Lei
- Laboratory of Amorphous Matter and Science
- School of Materials Science and Engineering
- Hefei University of Technology
- Hefei
- China
| | - Rulong Zhou
- Laboratory of Amorphous Matter and Science
- School of Materials Science and Engineering
- Hefei University of Technology
- Hefei
- China
| | - Bingyan Qu
- Laboratory of Amorphous Matter and Science
- School of Materials Science and Engineering
- Hefei University of Technology
- Hefei
- China
| | - Dongdong Li
- Laboratory of Amorphous Matter and Science
- School of Materials Science and Engineering
- Hefei University of Technology
- Hefei
- China
| | - Bo Zhang
- Laboratory of Amorphous Matter and Science
- School of Materials Science and Engineering
- Hefei University of Technology
- Hefei
- China
| | - Xiao Cheng Zeng
- Department of Chemistry
- University of Nebraska-Lincoln
- Lincoln
- USA
- Collaborative Innovation Center of Chemistry for Energy Materials
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15
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Li N, Manoun B, Tang L, Ke F, Liu F, Dong H, Lazor P, Yang W. Pressure-Induced Structural and Electronic Transition in Sr2ZnWO6 Double Perovskite. Inorg Chem 2016; 55:6770-5. [PMID: 27308777 DOI: 10.1021/acs.inorgchem.6b01091] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
High-pressure structural and electrical properties of Sr2ZnWO6 double perovskite were investigated using in situ angle-dispersive synchrotron X-ray diffraction (XRD), Raman, and alternating current (AC) impedance spectroscopy. A structural transition from monoclinic (P21/n) to triclinic (P1̅) phase around 9 GPa was observed due to the pressure-induced distortion of (W, Zn)O6 octahedron. In situ high-pressure Raman spectroscopy showed the increasing interaction among O-W-O in WO6 octahedron with pressure and a transition pressure consistent with the XRD results. From the AC impedance spectroscopy measurements, the resistivity increased steeply by ∼1 order of magnitude around 11 GPa, indicating an electronic transition accompanying the symmetry change. The increase in the interaction among O-W-O enhances the attraction of O(2-) electrons toward W(6+), thus increasing the covalence, which in turn lowers the charge transfer energy between O(2-) and W(6+) and induces the resistivity increase under high pressure.
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Affiliation(s)
- Nana Li
- Center for High Pressure Science and Technology Advanced Research , Shanghai 201203, China
| | - Bouchaib Manoun
- Universite Hassan 1er , Laboratoire des Sciences des Matériaux, des Milieux et de la modélisation (LS3M), 25000, Khouribga, Morocco
| | - Lingyun Tang
- Center for High Pressure Science and Technology Advanced Research , Shanghai 201203, China.,High Pressure Synergetic Consortium, Geophysical Laboratory, Carnegie Institution of Washington , Argonne, Illinois 60439, United States
| | - Feng Ke
- Center for High Pressure Science and Technology Advanced Research , Shanghai 201203, China
| | - Fengliang Liu
- Center for High Pressure Science and Technology Advanced Research , Shanghai 201203, China.,The state Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University , Shanghai 200433, China
| | - Haini Dong
- Center for High Pressure Science and Technology Advanced Research , Shanghai 201203, China.,Key Laboratory of High-temperature and High-pressure Study of the Earth's Interior, Institute of Geochemistry, Chinese Academy of Sciences , Guizhou 550081, China
| | - Peter Lazor
- Department of Earth Sciences, Uppsala University , SE-752 36 Uppsala, Sweden
| | - Wenge Yang
- Center for High Pressure Science and Technology Advanced Research , Shanghai 201203, China.,High Pressure Synergetic Consortium, Geophysical Laboratory, Carnegie Institution of Washington , Argonne, Illinois 60439, United States
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16
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Wang L, Huang X, Li D, Huang Y, Bao K, Li F, Wu G, Liu B, Cui T. Pressure-induced structural transformation of CaC2. J Chem Phys 2016; 144:194506. [DOI: 10.1063/1.4948705] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Lu Wang
- State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, People’s Republic of China
| | - Xiaoli Huang
- State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, People’s Republic of China
| | - Da Li
- State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, People’s Republic of China
| | - Yanping Huang
- State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, People’s Republic of China
| | - Kuo Bao
- State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, People’s Republic of China
| | - Fangfei Li
- State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, People’s Republic of China
| | - Gang Wu
- State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, People’s Republic of China
| | - Bingbing Liu
- State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, People’s Republic of China
| | - Tian Cui
- State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, People’s Republic of China
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17
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Woerner WR, Qian GR, Oganov AR, Stephens PW, Dharmagunawardhane HAN, Sinclair A, Parise JB. Combined Theoretical and in Situ Scattering Strategies for Optimized Discovery and Recovery of High-Pressure Phases: A Case Study of the GaN–Nb2O5 System. Inorg Chem 2016; 55:3384-92. [DOI: 10.1021/acs.inorgchem.5b02791] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | | | | | | | | | - John B. Parise
- Photon
Sciences, Brookhaven National Laboratory, Upton, New York 11934, United States
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18
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Li P, Zhou R, Zeng XC. Computational analysis of stable hard structures in the Ti-B system. ACS APPLIED MATERIALS & INTERFACES 2015; 7:15607-15617. [PMID: 26125540 DOI: 10.1021/acsami.5b04332] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The lowest energy crystalline structures of various stoichiometric titanium boride (Ti-B) intermetallic compounds are sought based on density functional theory combined with the particle-swarm optimization (PSO) technique. Besides three established experimental structures, i.e., FeB-type TiB, AlB2-type, and Ta3B4-type Ti3B4, we predict additional six metastable phases at these stoichiometric ratios, namely, α- and β-phases for TiB, TiB2, and Ti3B4, respectively. Moreover, we predict the most stable crystalline structures of four new titanium boride compounds with different stoichiometric ratios: Ti2B-PSA, Ti2B3-PSB, TiB3-PSC, and TiB4-PSD. Notably, Ti2B-PSA is shown to have lower formation energy (thus higher stability) than the previously proposed Al2Cu-type Ti2B. The computed convex-hull and phonon dispersion relations confirm that all the newly predicted Ti-B intermetallic crystals are thermodynamically and dynamically stable. Remarkably, the predicted α-TiB2 and β-TiB2 show semi-metal-like electronic properties and possess high Vickers hardnesses (39.4 and 39.6 GPa), very close to the lower limit of superhard materials (40 GPa). Analyses of band structure, density of states, electronic localization function, and various elastic moduli provide further understanding of the electronic and mechanical properties of the intermetallic titanium borides. We hope the newly predicted hard intermetallic titanium borides coupled with desirable electronic properties and high elastic modulus will motivate future experimental synthesis for applications such as high-temperature structural materials.
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Affiliation(s)
- Pengfei Li
- †Hefei National Laboratory for Physical Sciences at Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- §Department of Chemistry and Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Rulong Zhou
- ‡School of Science and Engineering of Materials, Hefei University of Technology, Hefei, Anhui 230009, China
| | - Xiao Cheng Zeng
- †Hefei National Laboratory for Physical Sciences at Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- §Department of Chemistry and Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
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19
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Investigation of exotic stable calcium carbides using theory and experiment. Nat Commun 2015; 6:6974. [PMID: 25959292 PMCID: PMC4432597 DOI: 10.1038/ncomms7974] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 03/18/2015] [Indexed: 11/23/2022] Open
Abstract
It is well known that pressure causes profound changes in the properties of atoms and chemical bonding, leading to the formation of many unusual materials. Here we systematically explore all stable calcium carbides at pressures from ambient to 100 GPa using variable-composition evolutionary structure predictions using the USPEX code. We find that Ca5C2, Ca2C, Ca3C2, CaC, Ca2C3 and CaC2 have stability fields on the phase diagram. Among these, Ca2C and Ca2C3 are successfully synthesized for the first time via high-pressure experiments with excellent structural correspondence to theoretical predictions. Of particular significance is the base-centred monoclinic phase (space group C2/m) of Ca2C, a quasi-two-dimensional metal with layers of negatively charged calcium atoms, and the primitive monoclinic phase (space group P21/c) of CaC with zigzag C4 groups. Interestingly, strong interstitial charge localization is found in the structure of R-3m-Ca5C2 with semi-metallic behaviour. Pressure causes profound changes in the properties of atoms and chemical bonding leading to unusual materials. Here, the authors investigate the Ca-C system and find that it becomes increasingly complex and develops a multitude of phases with various compositions and new structures at higher pressures.
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20
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Li Y, Wang Y, Pickard CJ, Needs RJ, Wang Y, Ma Y. Metallic icosahedron phase of sodium at terapascal pressures. PHYSICAL REVIEW LETTERS 2015; 114:125501. [PMID: 25860756 DOI: 10.1103/physrevlett.114.125501] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Indexed: 06/04/2023]
Abstract
Alkali metals exhibit unexpected structures and electronic behavior at high pressures. Compression of metallic sodium (Na) to 200 GPa leads to the stability of a wide-band-gap insulator with the double hexagonal hP4 structure. Post-hP4 structures remain unexplored, but they are important for addressing the question of the pressure at which Na reverts to a metal. Here, we report the reentrant metallicity of Na at the very high pressure of 15.5 terapascal (TPa), predicted using first-principles structure searching simulations. Na is therefore insulating over the large pressure range of 0.2-15.5 TPa. Unusually, Na adopts an oP8 structure at pressures of 117-125 GPa and the same oP8 structure at 1.75-15.5 TPa. The metallization of Na occurs on the formation of a stable and striking body-centered cubic cI24 electride structure consisting of Na_{12} icosahedra, each housing at its center about one electron that is not associated with any Na ions.
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Affiliation(s)
- Yinwei Li
- School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116, China
- State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China
| | - Yanchao Wang
- State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China
| | - Chris J Pickard
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Richard J Needs
- Theory of Condensed Matter Group, Cavendish Laboratory, J J Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Yi Wang
- Natural Science Research Center, Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology, Harbin 150080, China
| | - Yanming Ma
- State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China
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21
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Cheng X, Li R, Li D, Li Y, Chen XQ. Stable compositions and structures in the Na–Bi system. Phys Chem Chem Phys 2015; 17:6933-47. [DOI: 10.1039/c4cp05115g] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Predicted phase diversity and interesting properties of the Na–Bi system in the range of 0–320 GPa from first-principles calculations.
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Affiliation(s)
- Xiyue Cheng
- Shenyang National Laboratory for Materials Science
- Institute of Metal Research
- Chinese Academy of Sciences
- Shenyang 110016
- China
| | - Ronghan Li
- Shenyang National Laboratory for Materials Science
- Institute of Metal Research
- Chinese Academy of Sciences
- Shenyang 110016
- China
| | - Dianzhong Li
- Shenyang National Laboratory for Materials Science
- Institute of Metal Research
- Chinese Academy of Sciences
- Shenyang 110016
- China
| | - Yiyi Li
- Shenyang National Laboratory for Materials Science
- Institute of Metal Research
- Chinese Academy of Sciences
- Shenyang 110016
- China
| | - Xing-Qiu Chen
- Shenyang National Laboratory for Materials Science
- Institute of Metal Research
- Chinese Academy of Sciences
- Shenyang 110016
- China
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22
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Li P, Zhou R, Zeng XC. The search for the most stable structures of silicon-carbon monolayer compounds. NANOSCALE 2014; 6:11685-11691. [PMID: 25185699 DOI: 10.1039/c4nr03247k] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The most stable structures of two-dimensional (2D) silicon-carbon monolayer compounds with different stoichiometric compositions (i.e., Si : C ratio = 2 : 3, 1 : 3 and 1 : 4) are predicted for the first time based on the particle-swarm optimization (PSO) technique combined with density functional theory optimization. Although the 2D Si-C monolayer compounds considered here are rich in carbon, many of the low-energy metastable and the lowest-energy silicon-carbon structures are not graphene (carbon monolayer) like. Phonon-spectrum calculations and ab initio molecular dynamics simulations were also performed to confirm the dynamical stability of the predicted most stable 2D silicon-carbon structures as well their thermal stability at elevated temperature. The computed electronic band structures show that all three predicted silicon-carbon compounds are semiconductors with direct or indirect bandgaps. Importantly, their bandgaps are predicted to be close to those of bulk silicon or bulk germanium. If confirmed in the laboratory, these 2D silicon-carbon compounds with different stoichiometric compositions may be exploited for future applications in nanoelectronic devices.
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Affiliation(s)
- Pengfei Li
- Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China.
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23
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Raza Z, Errea I, Oganov AR, Saitta AM. Novel superconducting skutterudite-type phosphorus nitride at high pressure from first-principles calculations. Sci Rep 2014; 4:5889. [PMID: 25074347 PMCID: PMC4115206 DOI: 10.1038/srep05889] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 07/15/2014] [Indexed: 11/09/2022] Open
Abstract
State of the art variable composition structure prediction based on density functional theory demonstrates that two new stoichiometries of PN, PN3 and PN2, become viable at high pressure. PN3 has a skutterudite-like Immm structure and is metastable with positive phonon frequencies at pressures between 10 and 100 GPa. PN3 is metallic and is the first reported nitrogen-based skutterudite. Its metallicity arises from nitrogen p-states which delocalise across N4 rings characteristic of skutterudites, and it becomes a good electron-phonon superconductor at 10 GPa, with a Tc of around 18 K. The superconductivity arises from strongly enhanced electron-phonon coupling at lower pressures, originating primarily from soft collective P-N phonon modes. The PN2 phase is an insulator with P2/m symmetry and is stable at pressures in excess of 200 GPa.
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Affiliation(s)
- Zamaan Raza
- Sorbonne Universités, UPMC Univ. Paris 06, UMR 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), F-75005 Paris, France
- CNRS, UMR 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), F-75005 Paris, France
| | - Ion Errea
- Sorbonne Universités, UPMC Univ. Paris 06, UMR 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), F-75005 Paris, France
- Donostia International Physics Center (DIPC), Manuel de Lardizabal pasealekua 4, 20018 Donostia-San Sebastián, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain
| | - Artem R. Oganov
- Department of Geosciences, State University of New York, Stony Brook, NY 11794-2100, USA
- Center for Materials Design, Institute for Advanced Computational Science, State University of New York, Stony Brook, NY 11794-2011, USA
- Moscow Institute of Physics and Technology, 9 Institutskiy Lane, Dolgoprudny City, Moscow Region, 141700, Russian Federation
- Northwestern Polytechnical University, Xi'an, 710072, China
| | - A. Marco Saitta
- Sorbonne Universités, UPMC Univ. Paris 06, UMR 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), F-75005 Paris, France
- CNRS, UMR 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), F-75005 Paris, France
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24
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Holzapfel WB. Structures of the elements - crystallography and art. ACTA CRYSTALLOGRAPHICA SECTION B, STRUCTURAL SCIENCE, CRYSTAL ENGINEERING AND MATERIALS 2014; 70:429-435. [PMID: 24892589 DOI: 10.1107/s2052520614005277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 03/07/2014] [Indexed: 06/03/2023]
Abstract
Since simple data tables on phase transitions and structural systematics of the elements over a wide range of pressure and temperature are difficult to comprehend, this paper illustrates these systematics with some artwork together with an artist's view of the equations of states for the elements.
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Affiliation(s)
- Wilfried B Holzapfel
- Physics Department, University of Paderborn, Warburger Str. 100, D-33095 Paderborn, Germany
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25
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Miao MS, Hoffmann R. High pressure electrides: a predictive chemical and physical theory. Acc Chem Res 2014; 47:1311-7. [PMID: 24702165 DOI: 10.1021/ar4002922] [Citation(s) in RCA: 165] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Electrides, in which electrons occupy interstitial regions in the crystal and behave as anions, appear as new phases for many elements (and compounds) under high pressure. We propose a unified theory of high pressure electrides (HPEs) by treating electrons in the interstitial sites as filling the quantized orbitals of the interstitial space enclosed by the surrounding atom cores, generating what we call an interstitial quasi-atom, ISQ. With increasing pressure, the energies of the valence orbitals of atoms increase more significantly than the ISQ levels, due to repulsion, exclusion by the atom cores, effectively giving the valence electrons less room in which to move. At a high enough pressure, which depends on the element and its orbitals, the frontier atomic electron may become higher in energy than the ISQ, resulting in electron transfer to the interstitial space and the formation of an HPE. By using a He lattice model to compress (with minimal orbital interaction at moderate pressures between the surrounding He and the contained atoms or molecules) atoms and an interstitial space, we are able to semiquantitatively explain and predict the propensity of various elements to form HPEs. The slopes in energy of various orbitals with pressure (s > p > d) are essential for identifying trends across the entire Periodic Table. We predict that the elements forming HPEs under 500 GPa will be Li, Na (both already known to do so), Al, and, near the high end of this pressure range, Mg, Si, Tl, In, and Pb. Ferromagnetic electrides for the heavier alkali metals, suggested by Pickard and Needs, potentially compete with transformation to d-group metals.
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Affiliation(s)
- Mao-Sheng Miao
- Beijing Computational Science Research Center, Beijing, 100084, China
- Materials
Research Lab., University of California—Santa Barbara, Santa Barbara, California 93106-5050, United States
| | - Roald Hoffmann
- Department
of Chemistry and Chemical Biology, Baker
Laboratory, Cornell University, Ithaca, New York 14853-1301, United States
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26
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Ning J, Zhang X, Zhang S, Sun N, Wang L, Ma M, Liu R. Pressure-induced pseudoatom bonding collapse and isosymmetric phase transition in Zr2Cu: first-principles predictions. J Chem Phys 2013; 139:234504. [PMID: 24359377 DOI: 10.1063/1.4846995] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The structural evolution of tetragonal Zr2Cu has been investigated under high pressures up to 70 GPa by means of density functional theory. Our calculations predict a pressure-induced isosymmetric transition where the tetragonal symmetry (I4/mmm) is retained during the entire compression as well as decompression process while its axial ratio (c/a) undergoes a transition from ~3.5 to ~4.2 at around 35 GPa with a hysteresis width of about 4 GPa accompanied by an obvious volume collapse of 1.8% and anomalous elastic properties such as weak mechanical stability, dramatically high elastic anisotropy, and low Young's modulus. Crystallographically, the tetragonal axial ratio shift renders this transition analogous to a simple bcc-to-fcc structural transition, which implies it might be densification-driven. Electronically, the ambient Zr2Cu is uncovered with an intriguing pseudo BaFe2As2-type structure, which upon the phase transition undergoes an electron density topological change and collapses to an atomic-sandwich-like structure. The pseudo BaFe2As2-type structure is demonstrated to be shaped by hybridized dxz + yz electronic states below Fermi level, while the high pressure straight Zr-Zr bonding is accommodated by electronic states near Fermi level with dx(2) - y(2) dominant features.
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Affiliation(s)
- Jinliang Ning
- State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, People's Republic of China
| | - Xinyu Zhang
- State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, People's Republic of China
| | - Suhong Zhang
- State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, People's Republic of China
| | - Na Sun
- State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, People's Republic of China
| | - Limin Wang
- State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, People's Republic of China
| | - Mingzhen Ma
- State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, People's Republic of China
| | - Riping Liu
- State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, People's Republic of China
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27
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Li YL, Luo W, Chen XJ, Zeng Z, Lin HQ, Ahuja R. Formation of Nanofoam carbon and re-emergence of Superconductivity in compressed CaC6. Sci Rep 2013; 3:3331. [PMID: 24276612 PMCID: PMC3840379 DOI: 10.1038/srep03331] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 11/06/2013] [Indexed: 11/10/2022] Open
Abstract
Pressure can tune material's electronic properties and control its quantum state, making some systems present disconnected superconducting region as observed in iron chalcogenides and heavy fermion CeCu2Si2. For CaC6 superconductor (Tc of 11.5 K), applying pressure first Tc increases and then suppresses and the superconductivity of this compound is eventually disappeared at about 18 GPa. Here, we report a theoretical finding of the re-emergence of superconductivity in heavily compressed CaC6. The predicted phase III (space group Pmmn) with formation of carbon nanofoam is found to be stable at wide pressure range with a Tc up to 14.7 K at 78 GPa. Diamond-like carbon structure is adhered to the phase IV (Cmcm) for compressed CaC6 after 126 GPa, which has bad metallic behavior, indicating again departure from superconductivity. Re-emerged superconductivity in compressed CaC6 paves a new way to design new-type superconductor by inserting metal into nanoporous host lattice.
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Affiliation(s)
- Yan-Ling Li
- School of Physics and Electronic Engineering, Jiangsu Normal University, 221116, Xuzhou, People's Republic of China
- Condensed Matter Theory Group, Department of Physics and Astronomy, Uppsala University, P.O. Box 516, SE-751 20 Uppsala, Sweden
| | - Wei Luo
- Condensed Matter Theory Group, Department of Physics and Astronomy, Uppsala University, P.O. Box 516, SE-751 20 Uppsala, Sweden
| | - Xiao-Jia Chen
- Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
- Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC 20015, U.S.A
- Center for High pressure Science and Technology Advanced Research, Shanghai 201203, People's Republic of China
| | - Zhi Zeng
- Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - Hai-Qing Lin
- Beijing Computational Science Research Center, Beijing 100089, People's Republic of China
| | - Rajeev Ahuja
- Condensed Matter Theory Group, Department of Physics and Astronomy, Uppsala University, P.O. Box 516, SE-751 20 Uppsala, Sweden
- Applied Material PhysicsPeople's Republic of China, Department of Materials Science and Engineering, Royal Institute of Technology (KTH), SE-100 44, Stockholm, Sweden
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28
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Di Gennaro M, Saha SK, Verstraete MJ. Role of dynamical instability in the ab initio phase diagram of calcium. PHYSICAL REVIEW LETTERS 2013; 111:025503. [PMID: 23889418 DOI: 10.1103/physrevlett.111.025503] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Indexed: 06/02/2023]
Abstract
In the 32-119 GPa pressure range and at room temperature, a simple cubic phase was reported for calcium in many different experiments. Standard linear response theory, both within density functional perturbation theory and frozen phonon calculations, presents dynamical instabilities for the simple cubic structure in the whole pressure range. Many other possible candidate phases, as well as several possible stabilization mechanisms for the simple cubic phase, have been proposed as the result of ab initio predictions but the role of temperature on the relative stability of the different phases has not been systematically investigated. We revisit the stability of the three most important candidate phases of calcium for the intermediate pressure range and for various temperatures, taking explicitly into account thermal corrections relative to electronic as well as phononic entropy and anharmonic contributions. This corrects the discrepancies among previous theoretical results and experiments and presents a different picture of the temperature driven phase transition, which results from dynamical anharmonic stabilization of simple cubic and destabilization of the tetragonal phase.
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Affiliation(s)
- Marco Di Gennaro
- Department of Physics and European Theoretical Spectroscopy Facility, Université de Liège, Alleé du 6 août 17, Sart Tilman, B-4000, Liège, Belgium.
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29
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Fujihisa H, Nakamoto Y, Sakata M, Shimizu K, Matsuoka T, Ohishi Y, Yamawaki H, Takeya S, Gotoh Y. Ca-VII: a chain ordered host-guest structure of calcium above 210 GPa. PHYSICAL REVIEW LETTERS 2013; 110:235501. [PMID: 25167509 DOI: 10.1103/physrevlett.110.235501] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Indexed: 06/03/2023]
Abstract
The recently discovered high pressure phase VII of calcium [M. Sakata et al., Phys. Rev. B 83, 220512(R) (2011)] has the highest superconducting transition temperature (T(c)) of 29 K among all the elements. Understanding the cause for such a high T(c) state is necessary to clarify its crystal structure. The structure of this phase was determined by an x-ray powder diffraction experiment and a density functional theory calculation and was not found to be the usual host-guest type but consisted of a 2×2 supercell in the tetragonal ab plane with a commensurate host-guest ratio of 4/3 along the c axis containing 128 atoms.
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Affiliation(s)
- Hiroshi Fujihisa
- National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Yuki Nakamoto
- KYOKUGEN, Center for Quantum Science and Technology under Extreme Conditions, Osaka University, Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan
| | - Masafumi Sakata
- KYOKUGEN, Center for Quantum Science and Technology under Extreme Conditions, Osaka University, Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan
| | - Katsuya Shimizu
- KYOKUGEN, Center for Quantum Science and Technology under Extreme Conditions, Osaka University, Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan
| | - Takahiro Matsuoka
- KYOKUGEN, Center for Quantum Science and Technology under Extreme Conditions, Osaka University, Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan and JASRI/SPring-8, Kouto, Mikazuki-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Yasuo Ohishi
- JASRI/SPring-8, Kouto, Mikazuki-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Hiroshi Yamawaki
- National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Satoshi Takeya
- National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Yoshito Gotoh
- National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
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30
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Liu H, Cui W, Ma Y. Hybrid functional study rationalizes the simple cubic phase of calcium at high pressures. J Chem Phys 2012; 137:184502. [DOI: 10.1063/1.4765326] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Chen Y, Hu QM, Yang R. Predicted suppression of the superconducting transition of new high-pressure yttrium phases with increasing pressure from first-principles calculations. PHYSICAL REVIEW LETTERS 2012; 109:157004. [PMID: 23102356 DOI: 10.1103/physrevlett.109.157004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Indexed: 06/01/2023]
Abstract
Structure searches for new high-pressure phases of Y metal have been performed by using evolutionary algorithms in conjunction with a first-principles, pseudopotential plane-wave method based on density functional theory. The oF16-Fddd and hP3-P3(1)21 phases are predicted to be energetically favorable at pressures over 97 GPa. These two phases are shown to be dynamically stable by computing their phonon dispersions. We thus propose that oF16-Fddd and hP3-P3(1)21 are the most probable crystal structures Y may take in the 97-206 GPa range. The superconducting critical temperatures (T(c)) of the new phases are estimated using the Allen-Dynes formula. The T(c) is predicted to decrease with increasing pressure over about 100 GPa, in sharp contrast to its observed monotonic increase under lower pressure. The electronic origins of the stabilities of the proposed high-pressure phases have also been investigated.
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Affiliation(s)
- Yue Chen
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China.
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32
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Calcium with the β-tin structure at high pressure and low temperature. Proc Natl Acad Sci U S A 2012; 109:16459-62. [PMID: 23012455 DOI: 10.1073/pnas.1214754109] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Using synchrotron high-pressure X-ray diffraction at cryogenic temperatures, we have established the phase diagram for calcium up to 110 GPa and 5-300 K. We discovered the long-sought for theoretically predicted β-tin structured calcium with I4(1)/amd symmetry at 35 GPa in a s mall low-temperature range below 10 K, thus resolving the enigma of absence of this lowest enthalpy phase. The stability and relations among various distorted simple-cubic phases in the Ca-III region have also been examined and clarified over a wide range of high pressures and low temperatures.
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Pressure-induced amorphous-to-amorphous configuration change in Ca-Al metallic glasses. Sci Rep 2012; 2:376. [PMID: 22530094 PMCID: PMC3332524 DOI: 10.1038/srep00376] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 04/10/2012] [Indexed: 11/28/2022] Open
Abstract
Pressure-induced amorphous-to-amorphous configuration changes in Ca-Al metallic glasses (MGs) were studied by performing in-situ room-temperature high-pressure x-ray diffraction up to about 40 GPa. Changes in compressibility at about 18 GPa, 15.5 GPa and 7.5 GPa during compression are detected in Ca80Al20, Ca72.7Al27.3, and Ca66.4Al33.6 MGs, respectively, whereas no clear change has been detected in the Ca50Al50 MG. The transfer of s electrons into d orbitals under pressure, reported for the pressure-induced phase transformations in pure polycrystalline Ca, is suggested to explain the observation of an amorphous-to-amorphous configuration change in this Ca-Al MG system. Results presented here show that the pressure induced amorphous-to-amorphous configuration is not limited to f electron-containing MGs.
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35
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Tse JS, Desgreniers S, Ohishi Y, Matsuoka T. Large amplitude fluxional behaviour of elemental calcium under high pressure. Sci Rep 2012; 2:372. [PMID: 22523635 PMCID: PMC3330680 DOI: 10.1038/srep00372] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 03/19/2012] [Indexed: 11/30/2022] Open
Abstract
Experimental evidences are presented showing unusually large and highly anisotropic vibrations in the “simple cubic” (SC) unit cell adopted by calcium over a broad pressure ranging from 30–90 GPa and at temperature as low as 40 K. X-ray diffraction patterns show a preferential broadening of the (110) Bragg reflection indicating that the atomic displacements are not isotropic but restricted to the [110] plane. The unusual observation can be rationalized invoking a simple chemical perspective. As the result of pressure-induced s → d transition, Ca atoms situated in the octahedral environment of the simple cubic structure are subjected to Jahn-Teller distortions. First-principles molecular dynamics calculations confirm this suggestion and show that the distortion is of dynamical nature as the cubic unit cell undergoes large amplitude tetragonal fluctuations. The present results show that, even under extreme compression, the atomic configuration is highly fluxional as it constantly changes.
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36
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Jalem R, Mochiduki Y, Nobuhara K, Nakayama M, Nogami M. Global minimum structure search in LixCoO2 composition using a hybrid evolutionary algorithm. Phys Chem Chem Phys 2012; 14:13095-100. [DOI: 10.1039/c2cp41905j] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Zhao Z, Zhou XF, Wang LM, Xu B, He J, Liu Z, Wang HT, Tian Y. Universal Phase Transitions of B1-Structured Stoichiometric Transition Metal Carbides. Inorg Chem 2011; 50:9266-72. [DOI: 10.1021/ic200356x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zhisheng Zhao
- State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
| | - Xiang-Feng Zhou
- School of Physics and Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, Nankai University, Tianjin 300071, China
| | - Li-Min Wang
- State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
| | - Bo Xu
- State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
| | - Julong He
- State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
| | - Zhongyuan Liu
- State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
| | - Hui-Tian Wang
- School of Physics and Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, Nankai University, Tianjin 300071, China
| | - Yongjun Tian
- State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
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38
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Errea I, Rousseau B, Bergara A. Anharmonic stabilization of the high-pressure simple cubic phase of calcium. PHYSICAL REVIEW LETTERS 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] [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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39
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Oganov AR, Lyakhov AO, Valle M. How evolutionary crystal structure prediction works--and why. Acc Chem Res 2011; 44:227-37. [PMID: 21361336 DOI: 10.1021/ar1001318] [Citation(s) in RCA: 412] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Once the crystal structure of a chemical substance is known, many properties can be predicted reliably and routinely. Therefore if researchers could predict the crystal structure of a material before it is synthesized, they could significantly accelerate the discovery of new materials. In addition, the ability to predict crystal structures at arbitrary conditions of pressure and temperature is invaluable for the study of matter at extreme conditions, where experiments are difficult. Crystal structure prediction (CSP), the problem of finding the most stable arrangement of atoms given only the chemical composition, has long remained a major unsolved scientific problem. Two problems are entangled here: search, the efficient exploration of the multidimensional energy landscape, and ranking, the correct calculation of relative energies. For organic crystals, which contain a few molecules in the unit cell, search can be quite simple as long as a researcher does not need to include many possible isomers or conformations of the molecules; therefore ranking becomes the main challenge. For inorganic crystals, quantum mechanical methods often provide correct relative energies, making search the most critical problem. Recent developments provide useful practical methods for solving the search problem to a considerable extent. One can use simulated annealing, metadynamics, random sampling, basin hopping, minima hopping, and data mining. Genetic algorithms have been applied to crystals since 1995, but with limited success, which necessitated the development of a very different evolutionary algorithm. This Account reviews CSP using one of the major techniques, the hybrid evolutionary algorithm USPEX (Universal Structure Predictor: Evolutionary Xtallography). Using recent developments in the theory of energy landscapes, we unravel the reasons evolutionary techniques work for CSP and point out their limitations. We demonstrate that the energy landscapes of chemical systems have an overall shape and explore their intrinsic dimensionalities. Because of the inverse relationships between order and energy and between the dimensionality and diversity of an ensemble of crystal structures, the chances that a random search will find the ground state decrease exponentially with increasing system size. A well-designed evolutionary algorithm allows for much greater computational efficiency. We illustrate the power of evolutionary CSP through applications that examine matter at high pressure, where new, unexpected phenomena take place. Evolutionary CSP has allowed researchers to make unexpected discoveries such as a transparent phase of sodium, a partially ionic form of boron, complex superconducting forms of calcium, a novel superhard allotrope of carbon, polymeric modifications of nitrogen, and a new class of compounds, perhydrides. These methods have also led to the discovery of novel hydride superconductors including the "impossible" LiH(n) (n=2, 6, 8) compounds, and CaLi(2). We discuss extensions of the method to molecular crystals, systems of variable composition, and the targeted optimization of specific physical properties.
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Affiliation(s)
- Artem R. Oganov
- Department of Geosciences and Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794-2100, United States
- Geology Department, Moscow State University, 119992 Moscow, Russia
| | - Andriy O. Lyakhov
- Department of Geosciences and Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794-2100, United States
| | - Mario Valle
- Data Analysis and Visualization Group, Swiss National Supercomputing Centre (CSCS), via Cantonale, Galleria 2, 6928 Manno, Switzerland
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Teweldeberhan AM, Dubois JL, Bonev SA. High-pressure phases of calcium: density-functional theory and diffusion quantum Monte Carlo approach. PHYSICAL REVIEW LETTERS 2010; 105:235503. [PMID: 21231479 DOI: 10.1103/physrevlett.105.235503] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Indexed: 05/30/2023]
Abstract
The phase diagram of Ca is examined using a combination of density-functional theory (DFT) and diffusion quantum Monte Carlo (DMC) calculations. Gibbs free energies of several competing structures are computed at pressures near 50 GPa. Existing disagreements for the stability of Ca both at low and room temperature are resolved with input from DMC. Furthermore, DMC calculations are performed on 0 K crystalline structures up to 150 GPa and it is demonstrated that the widely used generalized gradient approximation of DFT is insufficient to accurately account for the relative stability of the high-pressure phases of Ca. The results indicate that the theoretical phase diagram of Ca needs a revision.
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Affiliation(s)
- A M Teweldeberhan
- Lawrence Livermore National Laboratory, PO Box 808, Livermore, California 94550, USA
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