BiTeCl and BiTeBr: a comparative high-pressure optical study

Abstract

We here report a detailed high-pressure infrared transmission study of BiTeCl and BiTeBr. We follow the evolution of two band transitions: the optical excitation $\beta$ between two Rashba-split conduction bands, and the absorption $\gamma$ across the band gap. In the low pressure range, $p<4$~GPa, for both compounds $\beta$ is approximately constant with pressure and $\gamma$ decreases, in agreement with band structure calculations. In BiTeCl, a clear pressure-induced phase transition at 6~GPa leads to a different ground state. For BiTeBr, the pressure evolution is more subtle, and we discuss the possibility of closing and reopening of the band gap. Our data is consistent with a Weyl phase in BiTeBr at 5$-$6~GPa, followed by the onset of a structural phase transition at 7~GPa.

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References in corpus (5)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Weyl semimetals from noncentrosymmetric topological insulators
• Strongly spin-orbit coupled two-dimensional electron gas emerging near the surface of polar semiconductors
• Optical properties of BiTeBr and BiTeCl
• Pressure effects on crystal and electronic structure of bismuth tellurohalides

Cited by in corpus (1)

• Temperature dependence of the bulk Rashba splitting in the bismuth tellurohalides