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.
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We thank B. -J. Yang and E. G. Moon for helpful discussions. This work was supported by the National Research Foundation of Korea (NRF) through the SRC (No. 2011-0030785), the Max Planck POSTECH/ KOREA Research Initiative Program (No. 2011-0031558) and also by IBS (No. IBS-R014-D1-2014-a02). W. K. is supported by the NRF grants funded by the Korea Government (MSIP) (No. 2015-001948 and No. 2010-00453). The work at the NHMFL was supported by National Science Foundation Cooperative Agreement No. DMR-1157490, the State of Florida, and the U.S. Department of Energy. We also acknowledge the support of the HLD-HZDR, member of the European Magnetic Field Laboratory (EMFL).