Pressure-induced topological phase transition in the polar semiconductor BiTeBr

Abstract

We performed X-ray diffraction and electrical resistivity measurement up to pressures of 5 GPa and the first-principles calculations utilizing experimental structural parameters to investigate the pressure-induced topological phase transition in BiTeBr having a noncentrosymmetric layered structure (space group P 3m1). The P 3m1 structure remains stable up to pressures of 5 GPa; the ratio of lattice constants, c/a, has a minimum at pressures of 2.5 -3 GPa. In the same range, the temperature dependence of resistivity changes from metallic to semiconducting at 3 GPa and has a plateau region between 50 and 150 K in the semiconducting state. Meanwhile, the pressure variation of band structure shows that the bulk band-gap energy closes at 2.9 GPa and re-opens at higher pressures. Furthermore, according to the Wilson loop analysis, the topological nature of electronic states in noncentrosymmetric BiTeBr at 0 and 5 GPa are explicitly revealed to be trivial and non-trivial, respectively. These results strongly suggest that pressure-induced topological phase transition in BiTeBr occurs at the pressures of 2.9 GPa.

Pressure-induced structural and electronic transitions in kesterite-type Cu2ZnSnS4

“…Such pressure-induced electronic topological transitions constitute a common motif for layered materials and are evidenced by distinct compressibility and Raman intensity changes, without any alteration of the (average) crystalline symmetry. 58,[67][68][69] A thorough investigation of such a possibility, however, lies beyond the scope of the present paper.…”

Structural, vibrational, and electrical properties of 1T−TiTe2 under hydrostatic pressure: Experiments and theory

“…Here, we would like to emphasize that a similar trend was reported in the pressure range 2.0  2.9 GPa and 2.5  3.0 GPa in BiTeI and BiTeBr, respectively and these changes were interpreted as the signature of TQPT. 9,10 To get more insight about c/a ratio anomalies, the pressure dependent Te(1)  Te(2) contact distance is plotted in Fig. S3.…”

“…18 Recently, Ohmura et al, showed that bismuth tellurihalide BiTeBr (S.G: P3m1, Eg = 0.55 eV) undergoes a TQPT at 2.5  3.0 GPa using resistivity and synchrotron XRD measurements under pressure. 10 The above examples provide strong basis for using such indirect methods to study pressure induced TQPT in the SOC systems.…”

“…Indeed hydrostatic pressure induced TQPT has been observed in several systems like BiTeI, BiTeBr, and Sb2Se3. [9][10][11] Due to its technological importance, a considerable number of materials have been theoretically predicted as a topological insulator under high-pressure. However, a direct experimental detection of band inversion with the high-pressure setup is challenging to perform.…”

“…However the indirect evidence of TQPT can be obtained from a combination of transport, synchrotron x-ray diffraction (XRD) and Raman linewidth anomalies which originate from charge density redistribution and electron phonon coupling during TQPT transition. [9][10][11]14,15 For instance, a combined synchrotron powder XRD and infrared spectroscopy measurements on BiTeI (space group S.G: P3m1, band gap Eg = 0.38 eV) revealed a correlation between band gap closing and band inversion with a minimum of c/a ratio in the pressure range 2.0  2.9 GPa. 9,16 Interestingly, a phonon linewidth anomaly (unusual electron phonon coupling) of E mode at ~ 3.0 GPa has been observed during TQPT in BiTeI.…”