Electron-Phonon Coupling and Quantum Correction to Topological Magnetoconductivity in Bi2GeTe4

Abstract

We report on structure, vibrational properties and weak-antilocalization-(WAL-) induced quantum correction to magnetoconductivity in single crystal Bi2GeTe4. Surface band structure calculations show a single Dirac cone corresponding to topological surface states in Bi2GeTe4. An estimated phase coherence length, l_{\phi} ~ 143 nm and prefactor {\alpha} ~ - 1.54 from Hikami-Larkin-Nagaoka fitting of magnetoconductivity describe the quantum correction to conductivity. An anomalous temperature dependence of A1g Raman modes confirms enhanced electron-phonon interactions. Our results establish the involvement of vibrations of Bi-Te with existence of topological surface states and WAL in Bi2GeTe4.