Intrinsic Electron-Phonon Resistivity in Bi2Se3 in the Topological Regime

TL;DR

This study investigates the temperature-dependent electrical properties of the topological surface state in Bi2Se3, revealing intrinsic electron-phonon scattering limits that affect conductivity and mobility.

Contribution

It provides the first quantitative analysis of intrinsic electron-phonon resistivity in Bi2Se3's topological surface state, linking experimental data with theoretical modeling.

Findings

Carrier density varies with temperature near the Dirac point due to bulk valence band activation.

Linear resistivity vs. temperature indicates dominant electron-acoustic phonon scattering.

Intrinsic conductivity limit at room temperature is approximately 550 μS per surface.

Abstract

We measure the temperature-dependent carrier density and resistivity of the topological surface state of thin exfoliated Bi2Se3 in the absence of bulk conduction. When the gate-tuned chemical potential is near or below the Dirac point the carrier density is strongly temperature dependent reflecting thermal activation from the nearby bulk valence band, while above the Dirac point, unipolar n-type surface conduction is observed with negligible thermal activation of bulk carriers. In this regime linear resistivity vs. temperature reflects intrinsic electron-acoustic phonon scattering. Quantitative comparison with a theoretical transport calculation including both phonon and disorder effects gives the ratio of deformation potential to Fermi velocity D/\hbarvF = 4.7 {\AA}-1. This strong phonon scattering in the Bi2Se3 surface state gives intrinsic limits for the conductivity and charge carrier mobility at room temperature of ~550 {\mu}S per surface and ~10,000 cm2/Vs.