Abstract
Electrical-field control of the carrier density of topological insulators (TIs) has greatly expanded the possible practical use of these materials. However, the combination of low-temperature local probe studies and a gate tunable TI device remains challenging. We have overcome this limitation by scanning tunneling microscopy and spectroscopy measurements on in situ molecular-beam epitaxy grown BiSe films on SrTiO substrates with prepatterned electrodes. Using this gating method, we are able to tune the Fermi level of the top surface states within a range of ≈250 meV on a 3-nm-thick BiSe device. We report field effect studies of the surface-state dispersion, band gap, and electronic structure at the Fermi level.
- Received 16 January 2013
DOI:https://doi.org/10.1103/PhysRevB.87.115410
©2013 American Physical Society