Towards temperature-induced topological phase transition in SnTe: A first-principles study

Abstract

The temperature renormalization of the bulk band structure of a topological crystalline insulator, SnTe, is calculated using first principles methods. We explicitly include the effect of thermalexpansion-induced modification of electronic states and their band inversion on electron-phonon interaction. We show that the direct gap decreases with temperature, as both thermal expansion and electron-phonon interaction drive SnTe towards the phase transition to a topologically trivial phase as temperature increases. The band gap renormalization due to electron-phonon interaction exhibits a non-linear dependence on temperature as the material approaches the phase transition, while the lifetimes of the conduction band states near the band edge show a non-monotonic behavior with temperature. These effects should have important implications on bulk electronic and thermoelectric transport in SnTe and other topological insulators.

Investigating the effect of temperature dependent many-body interactions on bulk electronic structures and the robust nature of (001) surface states of SnTe

“…It is observed from the figure that the values of bandgap are monotonically decreasing with increasing the temperature, which have a good agreement with previous theoretical and experimental works on this compound 61,62 . Recent theoretical work on this compound with considering the EPI is also suggesting the similar decreasing nature of bandgap with increasing temperature 18 . From our calculation, the decreasing rate of bandgap with respect to temperature upto 1500 K is found to be in order of 10 −5 , which shows 1/10 times of the previous observation on this compound 45,61 .…”

“…The extrapolated value of 1st (2nd) peak at 0 K is found to be ∼4 (∼2) meV, which is nicely agreed with the calculated value obtained from ground state G 0 W 0 method. Recently, Querales-Flores et al have shown the temperature dependent ImΣ(ω) which is obtained by considering the EPI 18 . By comparing this with our present work, it suggests that in lower temperature the lifetime of electron due to EPI and EEI are comparable but not in case of higher temperature.…”

“…This many-body interactions effect always brings more deeper understanding of any material, when temperature dependency is also included. ture of this material due to electron-phonon interactions (EPI) is studied by Querales-Flores et al 18 . But, the effect of EEI due to changing temperature is still not investigated.…”

Thermal topological phase transition in SnTe from \emph{ab-initio} calculations

“…There have been so far several theoretical attempts to tackle this problem. From the single particle density functional theory (DFT) perspective, attempts to assess the topological critical temperature are generally based on the closing of the gap at some finite temperature [7][8][9]. The conjuncture made in these papers is that topological invariants stay unaltered up to this point and the entire physics is determined by the single-particle gap inversion.…”

“…The explicit changes of the electronic structure due to thermal expansion are taken into account by performing calculations at the temperature-dependent lattice parameter, obtained from the linear thermal expansion coefficient as calculated in Ref. [9]. The electronic dispersion curves near the band edges at L are displayed in Fig.…”