1305.5485 (M. K. Tran et al.)

Structural transition and collapse of the gap and in BiTeI under
pressure    [PDF]

M. K. Tran, J. Levallois, P. Lerch, J. Teyssier, A. B. Kuzmenko, G. Autès, O. V. Yazyev, A. Ubaldini, E. Giannini, D. van der Marel, A. Akrap

BiTeI is a giant Rashba spin splitting system, in which a non-centro symmetric topological phase has recently been suggested to appear under high pressure. We investigated the optical properties of this compound, reflectivity and transmission, under pressures up to 15 GPa. The semiconducting gap collapses above p~9 GPa and does not reopen up to at least 15 GPa. The plasma edge, associated with intrinsically doped charge carriers, is smeared out through a phase transition at 9 GPa. Using high pressure Raman spectroscopy, we follow the vibrational modes of BiTeI and show that a structural transition occurs at 9 GPa. The closing of the band gap is caused by a change of symmetry, which possibly precludes the high-pressure topological phase.

View original: http://arxiv.org/abs/1305.5485