Electron-phonon coupling and quantum correction to topological magnetoconductivity in Bi2GeTe4

Abstract

We report structure, vibrational properties, and weak antilocalization-induced quantum correction to magnetoconductivity in single-crystal ${\mathrm{Bi}}_{2}\mathrm{Ge}{\mathrm{Te}}_{4}$. Surface band-structure calculations show a single Dirac cone corresponding to topological surface states in ${\mathrm{Bi}}_{2}\mathrm{Ge}{\mathrm{Te}}_{4}$. An estimated phase coherence length, ${l}_{\ensuremath{\phi}}\ensuremath{\sim}143\phantom{\rule{0.16em}{0ex}}\mathrm{nm}$ and prefactor \ensuremath{\alpha}\ensuremath{\sim}\ensuremath{-}1.54 from Hikami-Larkin-Nagaoka fitting of magnetoconductivity describe the quantum correction to conductivity. An anomalous temperature dependence of ${A}_{1g}$ Raman modes confirms enhanced electron-phonon interactions. Our results establish that electrons of the topological state can interact with the phonons involving the vibrations of Bi-Te in ${\mathrm{Bi}}_{2}\mathrm{Ge}{\mathrm{Te}}_{4}$.