Prediction of superconductivity in pressure-induced new silicon boride phases

Xiaowei Liang, Aitor Bergara, Yu Xie, Linyan Wang, Rongxin Sun, Yufei Gao, Xiang-Feng Zhou, Bo Xu, Julong He, Dongli Yu, Guoying Gao, and Yongjun Tian
Phys. Rev. B 101, 014112 – Published 27 January 2020
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Abstract

The crystal structures and properties of boron-silicon (B-Si) compounds under pressure have been systematically explored using particle swarm optimization structure prediction method in combination with first-principles calculations. Three new stoichiometries, B2Si, BSi, and BSi2, are predicted to be stable gradually under pressure, where increasing pressure favors the formation of silicon rich B-Si compounds. In the boron-rich compounds, the network of boron atoms changes from B12 icosahedron in the ambient phases to the similar buckled graphenelike layers in the high-pressure phases, which crystalize in the same P3¯m1 symmetry but with different numbers of boron layers between adjacent silicon layers. Phonon calculations show that these structures might be retained to ambient conditions as metastable phases. Further electron-phonon coupling calculations indicate that the high-pressure phases of boron-rich compounds might superconduct at 1 atm, with the highest Tc value of 21 K from the Allen-Dynes equation in P3¯m1 B2Si, which is much higher than the one observed in boron doped diamond-type silicon. Moreover, further fully anisotropic Migdal-Eliashberg calculations indicate that B2Si is a two-gap anisotropic superconductor and the estimated Tc might reach up to 30 K at 1 atm. On the silicon-rich side, BSi2 is predicted to be stable in the CuAl2-type structure. Our current results significantly enrich the phase diagram of the B-Si system and will stimulate further experimental study.

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  • Received 23 October 2019

DOI:https://doi.org/10.1103/PhysRevB.101.014112

©2020 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Xiaowei Liang1, Aitor Bergara2,3,4, Yu Xie5,*, Linyan Wang1, Rongxin Sun1, Yufei Gao1, Xiang-Feng Zhou1, Bo Xu1, Julong He1, Dongli Yu1, Guoying Gao1,†, and Yongjun Tian1

  • 1Center for High Pressure Science, State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
  • 2Departmento de Física de la Materia Condensada, Universidad del País Vasco, UPV/EHU, 48080 Bilbao, Spain
  • 3Donostia International Physics Center (DIPC), 20018 Donostia, Spain
  • 4Centro de Física de Materiales CFM, Centro Mixto CSIC-UPV/EHU, 20018 Donostia, Spain
  • 5Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education) & Innovation Center for Computational Physics Methods and Software & State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China

  • *xieyu@jlu.edu.cn
  • gaoguoying@ysu.edu.cn

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Vol. 101, Iss. 1 — 1 January 2020

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