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Title: Quasi-two-dimensional metallic hydrogen in diphosphide at a high pressure

Abstract

The structural, electronic, phonon, and other characteristics of the normal phases of phosphorus hydrides with stoichiometry PH{sub k} are analyzed. The properties of the initial substance, namely, diphosphine are calculated. In contrast to phosphorus hydrides with stoichiometry PH{sub 3}, a quasi-two-dimensional phosphorus-stabilized lattice of metallic hydrogen can be formed in this substance during hydrostatic compression at a high pressure. The formed structure with H–P–H elements is shown to be locally stable in phonon spectrum, i.e., to be metastable. The properties of diphosphine are compared with the properties of similar structures of sulfur hydrides.

Authors:
;  [1]
  1. National Research Nuclear University MEPhI (Russian Federation)
Publication Date:
OSTI Identifier:
22617209
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Experimental and Theoretical Physics; Journal Volume: 123; Journal Issue: 2; Other Information: Copyright (c) 2016 Pleiades Publishing, Inc.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; COMPARATIVE EVALUATIONS; COMPRESSION; COMPUTERIZED SIMULATION; HYDROGEN; HYDROGEN SULFIDES; HYDROSTATICS; PHONONS; PHOSPHORUS COMPOUNDS; PHOSPHORUS HYDRIDES; PRESSURE RANGE GIGA PA; SPECTRA; STOICHIOMETRY; SULFUR COMPOUNDS; TWO-DIMENSIONAL CALCULATIONS; TWO-DIMENSIONAL SYSTEMS

Citation Formats

Degtyarenko, N. N., and Mazur, E. A., E-mail: eugen-mazur@mail.ru. Quasi-two-dimensional metallic hydrogen in diphosphide at a high pressure. United States: N. p., 2016. Web. doi:10.1134/S1063776116070165.
Degtyarenko, N. N., & Mazur, E. A., E-mail: eugen-mazur@mail.ru. Quasi-two-dimensional metallic hydrogen in diphosphide at a high pressure. United States. doi:10.1134/S1063776116070165.
Degtyarenko, N. N., and Mazur, E. A., E-mail: eugen-mazur@mail.ru. 2016. "Quasi-two-dimensional metallic hydrogen in diphosphide at a high pressure". United States. doi:10.1134/S1063776116070165.
@article{osti_22617209,
title = {Quasi-two-dimensional metallic hydrogen in diphosphide at a high pressure},
author = {Degtyarenko, N. N. and Mazur, E. A., E-mail: eugen-mazur@mail.ru},
abstractNote = {The structural, electronic, phonon, and other characteristics of the normal phases of phosphorus hydrides with stoichiometry PH{sub k} are analyzed. The properties of the initial substance, namely, diphosphine are calculated. In contrast to phosphorus hydrides with stoichiometry PH{sub 3}, a quasi-two-dimensional phosphorus-stabilized lattice of metallic hydrogen can be formed in this substance during hydrostatic compression at a high pressure. The formed structure with H–P–H elements is shown to be locally stable in phonon spectrum, i.e., to be metastable. The properties of diphosphine are compared with the properties of similar structures of sulfur hydrides.},
doi = {10.1134/S1063776116070165},
journal = {Journal of Experimental and Theoretical Physics},
number = 2,
volume = 123,
place = {United States},
year = 2016,
month = 8
}
  • Na{sub 2}OsO{sub 4} crystals were grown by a NaCl flux method under high pressure. It crystallizes in the Ca{sub 2}IrO{sub 4}-type structure without having additional elements or metal vacancies, which are usually accommodated. It appears that Na{sub 2}OsO{sub 4} is a metal-stoichiometric Ca{sub 2}IrO{sub 4}-type compound never been synthesized to date. Na{sub 2}OsO{sub 4} has the octahedral environment of Os{sup 6+}O{sub 6} so that the electronic configuration is 5d{sup 2}, suggesting the magnetic S=1 ground state. However, magnetization, electrical resistivity, and specific heat measurements indicated that the non-magnetic S=0 state is much likely for Na{sub 2}OsO{sub 4} than the S=1more » state. Band structure calculations and the structure analysis found that the disagreement is probably due to the statically uniaxial compression of the OsO{sub 6} octahedra, resulting in splitting of the t{sub 2{sub g}} band.« less
  • The crystal structure of the quasi-one-dimensional cuprate Sr{sub 2}CuO{sub 3} has been studied under high pressure using neutron powder diffraction methods. Full structure refinements were undertaken, using the Rietveld method, with data acquired between room pressure and 0.55(1) GPa at room temperature. The compressibility of Sr{sub 2}CuO{sub 3} is anisotropic, a consequence of the ordered nature of the anion vacancies in this material. The effect of high pressure and chemical substitution on the crystal structure of the Sr{sub 2-x}Ca{sub x}CuO{sub 3} system is discussed and it is suggested that the substitution of Sr{sup 2+} by Ca{sup 2+} may constitute amore » 'chemical pressure' effect in this solid solution. The availability of accurate bond length compressibility data for Sr{sub 2}CuO{sub 3} may now allow an appraisal of the effect of applied pressure on the remarkable electronic properties of this material, through appropriate band structure calculations.« less
  • Na{sub 2}OsO{sub 4} crystals were grown by a NaCl flux method under high pressure. It crystallizes in the Ca{sub 2}IrO{sub 4}-type structure without having additional elements or metal vacancies, which are usually accommodated. It appears that Na{sub 2}OsO{sub 4} is a metal-stoichiometric Ca{sub 2}IrO{sub 4}-type compound never been synthesized to date. Na{sub 2}OsO{sub 4} has the octahedral environment of Os{sup 6+}O{sub 6} so that the electronic configuration is 5d{sup 2}, suggesting the magnetic S=1 ground state. However, magnetization, electrical resistivity, and specific heat measurements indicated that the non-magnetic S=0 state is much likely for Na{sub 2}OsO{sub 4} than the S=1more » state. Band structure calculations and the structure analysis found that the disagreement is probably due to the statically uniaxial compression of the OsO{sub 6} octahedra, resulting in splitting of the t{sub 2{sub g}} band. - Graphical abstract: Na{sub 2}OsO{sub 4} crystals were grown by a NaCl flux method under high pressure. It crystallizes in the Ca{sub 2}IrO{sub 4}-type structure comprising infinite Os{sup 6+}O{sub 6} octahedra (5d{sup 2}) chains. The crystal growth, the crystal structure, and the magnetic and electrical properties are reported.« less