Electronic topological transition and semiconductor-to-metal conversion of Bi2Te3 under high pressure

Abstract

Accurate high pressure in situ Hall-effect and temperature dependent electrical resistivity measurements have been carried out on Bi2Te3, a topological insulator. The pressure dependent electrical resistivity, Hall coefficient, carrier concentration, and mobility show the abnormal inflection points at 8, 12, and 17.8 GPa, indicating that the pressure-induced structural phase transitions of Bi2Te3 can result in a series of changes in the carrier transport behavior. In addition, the Hall coefficient shows a significant discontinuous change at 4 GPa, which is caused by the electronic topological transition. A sign inversion of Hall coefficient from positive to negative is found around 8 GPa. Furthermore, the temperature dependent electrical resistivity shows that the sample undergoes a semiconductor-to-metal conversion around 9.2 GPa, indicating that the insulating gap of Bi2Te3 becomes closed at this pressure. As the metallization occurs in the sample, the topological property of Bi2Te3 disappears.

Lattice dynamics and chemical bonding in Sb2Te3 from first-principles calculations

“…Since DFT studies of Bi 2 Se 3 42 and Bi 2 Te 3 have not been able to find a semiconductor to metal transitions and the experiments 10,18,20,22 exist controversy, further experimental and theoretical studies are needed before any general conclusions can be drawn about how pressure affects the semiconductor to conductor transitions in the group V chalcogenides.…”

“…12 The study of physical properties in these materials under compression is receiving increasing attention especially due to continuous experimental and theoretical developments. [13][14][15][16][17][18][19][20][21][22] The high-pressure phases II, III, and IV of Bi 2 Te 3 were recognized by x-ray diffraction experiments with the additional help from the particle swarm optimization algorithm. [13][14][15] The same type of phases was observed in Bi 2 Se 3 and Sb 2 Te 3 by the experiment group of Vilaplana et al 16,17 Here, the phase transition from the α phase I to the β phase II was between the rhombohedral R3m crystal structure to the monoclinic C2/m structure at 10 GPa for Bi 2 Se 3 , 7.4 GPa for Bi 2 Te 3 , and 7.7 GPa for Sb 2 Te 3 .…”

Pressure-induced electronic topological transition in Sb2S3

“…This sort of subtle changes in the resistivity value at high pressure has already been documented in Bi 2 Te 3 topological insulator. 43 The change in slope of the pressure Vs resistivity plot at 4 GPa supports the presence of anomaly of electronic states during ETT, which can possibly be due to electron-phonon coupling. The ETT reported to date in the metal chalcogenide A 2 B 3 series as shown in the Table 2.…”

Bi‐centric view of the isostructural phase transitions in α‐Bi2Se3 and α‐Bi2Te3

“…Moreover, Ovsyannikov et al showed that under compression Bi 2 Te 3 underwent an abrupt drop in a value of the thermopower near ∼1.5–2.0 GPa between two maxima, which was explained in terms of pressure‐driven changes in an electron structure. Zhang et al reported anomalies of high‐pressure Hall‐effect, carrier concentration, and mobility in Bi 2 Te 3 at 4 GPa, and they supported the occurrence of ETT. While anomalous variation of Seebeck coefficient and a strong redistribution of charge density were predicted and considered as an indicator of ETT in several first‐principles calculations , Achintya et al reported that there was no change in calculated Z 2 index in Bi 2 Se 3 at ∼3 GPa where Dirac conical surface electronic structure remained intact across the transition, and thus they proposed that the low pressure transition in Bi 2 Se 3 should not be related to any change in electronic topology.…”