Emergence of electron-phonon coupling in a dual topological insulator BiTe

Abstract

A versatile van der Waals epitaxy of BiTe, a newly discovered dual TI and a predicted higher order topological insulator (HOTI) thin film on muscovite mica is demonstrated using pulsed laser deposition. Topographic, structural and XPS analyses confirm the chemical homogeneity and high crystalline quality with large-area coverage with atomically smooth surface. The magneto transport data reveals weak anti-localization and electron-electron interaction driven insulating ground state with n-type character. An elaborate thickness, temperature and magnetic field dependence of transport data indicates a transition from coupled, partially coupled and fully decoupled surface states wherein 3D electron-electron and electron-phonon scatterings play significant role in dephasing mechanism, unlike 2D electron-electron dephasing in most TIs. Also from the fitting of the resistivity upturn we found that the coulomb screening factor (F) in thicker samples turns out to be negative which indicates the presence of the electron phonon coupling in those samples.