Abstract
We report the pressure-induced topological quantum phase transition of BiTeI single crystals using Shubnikov-de Haas oscillations of bulk Fermi surfaces. The sizes of the inner and the outer FSs of the Rashba-split bands exhibit opposite pressure dependence up to P = 3.35 GPa, indicating pressure-tunable Rashba effect. Above a critical pressure P ~ 2 GPa, the Shubnikov-de Haas frequency for the inner Fermi surface increases unusually with pressure, and the Shubnikov-de Haas oscillations for the outer Fermi surface shows an abrupt phase shift. In comparison with band structure calculations, we find that these unusual behaviors originate from the Fermi surface shape change due to pressure-induced band inversion. These results clearly demonstrate that the topological quantum phase transition is intimately tied to the shape of bulk Fermi surfaces enclosing the time-reversal invariant momenta with band inversion.
Highlights
We report the pressure-induced topological quantum phase transition of BiTeI single crystals using Shubnikov-de Haas oscillations of bulk Fermi surfaces
The well-separated oscillations are due to large difference in size between the inner Fermi surface (IFS) and the outer Fermi surface (OFS) of the Rashba bands[25,26]
Having understood the pressure-dependent FS sizes, we focus on determining the critical pressure Pc of the Topological quantum phase transition (TQPT) experimentally
Summary
We report the pressure-induced topological quantum phase transition of BiTeI single crystals using Shubnikov-de Haas oscillations of bulk Fermi surfaces. For the systems with broken inversion symmetry[18,19], low energy excitations at the TQPT are predicted to be a semi-Dirac type, having quadratic dispersion in one direction and linear in the others[6,7] Such intriguing electronic structures have been proposed in a noncentrosymmetric BiTeI at high pressures by recent band structure calculations[3]. These findings confirm the TQPT in BiTeI at high pressures, and demonstrate that quantum oscillations can provide an effective probe for detecting the pressure-induced TQPT in other candidate systems[22,23,24]
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