Pressure-induced electron topological transitions in Ba-doped Si clathrate

J. S. Tse, L. Yang, S. J. Zhang, C. Q. Jin, Ch. J. Sahle, C. Sternemann, A. Nyrow, V. Giordano, J. Z. Jiang, S. Yamanaka, S. Desgreniers, and C. A. Tulk

Phys. Rev. B 84, 184105 – Published 14 November 2011

Abstract

Ba $_{8}$ Si $_{46}$ is the archetype of the Si clathrates family. X-ray diffractions have revealed an unusual homothetic isostructural transition at ∼14–16 GPa. Raman experiments, however, suggested even more transitions at lower pressure. We present evidence showing that successive electronic topological transitions are responsible for the transformations. It is shown that the electronic structure of Ba $_{8}$ Si $_{46}$ is easily perturbed by the environment. Reverse Monte Carlo calculations and in-situ resistivity measurements revealed continual changes in the structure and electrical properties upon compression. This finding is corroborated by results of x-ray Raman scattering study in the vicinity of the Ba $N_{4, 5}$ and Si $L_{2, 3}$ absorption edges.

Received 23 October 2011

DOI:https://doi.org/10.1103/PhysRevB.84.184105

Authors & Affiliations

J. S. Tse^1,*, L. Yang², S. J. Zhang³, C. Q. Jin³, Ch. J. Sahle⁴, C. Sternemann⁴, A. Nyrow⁴, V. Giordano⁵, J. Z. Jiang⁶, S. Yamanaka⁷, S. Desgreniers⁸, and C. A. Tulk²

¹Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Canada S7N 5E2
²Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
³Institute of Physics, Chinese Academy of Sciences, PO Box 603, Beijing, 100190, People's Republic of China
⁴Technische Universität Dortmund, Fakultät Physik/DELTA, D-44221 Dortmund, Germany
⁵European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex 9, France
⁶International Center for New-Structured Materials (ICNSM), Zhejiang University and Laboratory of New-Structured Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou, People's Republic of China
⁷Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527, Japan
⁸Laboratoire de physique des solides denses, Department of Physics, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada

^*Corresponding author: jst634@mail.usask.ca

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Vol. 84, Iss. 18 — 1 November 2011

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