Abstract
We measure the temperature-dependent carrier density and resistivity of the topological surface state of thin exfoliated 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 -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. A quantitative comparison with a theoretical transport calculation including both phonon and disorder effects gives the ratio of deformation potential to Fermi velocity . This strong phonon scattering in the surface state gives intrinsic limits for the conductivity and charge carrier mobility at room temperature of per surface and .
- Received 25 May 2012
DOI:https://doi.org/10.1103/PhysRevLett.109.166801
© 2012 American Physical Society