Pressure Induced Topological Superconductivity of BiTeI Probed

by Tommy on 15/03/2017

Now that both Bi4I4 and BiTeI have been demonstrated to be unusual pressure induced topological superconductors, it would make sense to probe both of them more deeply with modern spectroscopic and ab initio analytical techniques. And it turns out that objective has already been performed on BiTeI.

Superconductivity Bordering Rashba Type Topological Transition, M. L. Jin, F. Sun, L. Y. Xing, S. J. Zhang, S. M. Feng, P. P. Kong, W. M. Li, X. C. Wang, J. L. Zhu, Y. W. Long, H. Y. Bai, C. Z. Gu, R. C. Yu, W. G. Yang, G. Y. Shen, Y. S. Zhao, H. K. Mao and C. Q. Jin, Scientific Reports 7, 39699 (4 January 2017), doi:10.1038/srep39699

Strong spin orbital interaction (SOI) can induce unique quantum phenomena such as topological insulators, the Rashba effect, or p-wave superconductivity. Combining these three quantum phenomena into a single compound has important scientific implications. Here we report experimental observations of consecutive quantum phase transitions from a Rashba type topological trivial phase to topological insulator state then further proceeding to superconductivity in a SOI compound BiTeI tuned via pressures. The electrical resistivity measurement with V shape change signals the transition from a Rashba type topological trivial to a topological insulator phase at 2 GPa, which is caused by an energy gap close then reopen with band inverse. Superconducting transition appears at 8 GPa with a critical temperature TC of 5.3 K. Structure refinements indicate that the consecutive phase transitions are correlated to the changes in the Bi–Te bond and bond angle as function of pressures. The Hall Effect measurements reveal an intimate relationship between superconductivity and the unusual change in carrier density that points to possible unconventional superconductivity.

Next up, Bi4I4.

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