Abstract
We report magnetotransport studies of ultrathin Sb films. Sb has been identified as a topologically nontrivial element; as a semimetal, however, the interior states dominate the transport in bulk samples. In the ultrathin films studied here, quantum confinement suppresses the interior transport such that surface transport accounts for about of the conduction in 10-bilayer-thick Sb structures. For thicknesses between 5 and 16 bilayers, the conduction increases linearly with film thickness, extrapolating to a finite remnant conductivity at zero film thickness. Weak antilocalization (WAL) is observed at low magnetic fields with thickness independent values of the phase breaking length and prefactor () implying surface transport coupled to residual interior conduction. At high fields we see an evolution of the magnetoresistance (MR) field dependence from parabolic to sublinear as a function of film thickness. The data are reproduced by a simple model combining parallel parabolic MR from the interior and WAL from the surface.
- Received 6 October 2014
- Revised 13 May 2015
DOI:https://doi.org/10.1103/PhysRevB.91.205317
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