Paper
23 February 2018 THz carrier dynamics and magnetotransport study of topological surface states in thin film Bi2Se3
Varun S. Kamboj, Angadjit Singh, Thierry Ferrus, Harvey E. Beere, Liam B. Duffy, Thorsten Hesjedal, Crispin H. W. Barnes, David A. Ritchie
Author Affiliations +
Abstract
The surface of a topological insulator harbors exotic topological states, protected against backscattering from disorder by time reversal symmetry. The study of these exotic quantum states not only provides an opportunity to explore fundamental phenomena in condensed matter physics, such as the spin Hall effect, but also lays the foundation for applications from quantum computing to spintronics. Conventional electrical measurements suffer from substantial bulk interference, making it difficult to clearly distinguish topological surface states from bulk states. Employing terahertz time-domain spectroscopy, we study the temperature-dependent optical behavior of a 23-quintuple-thick film of bismuth selenide (Bi2Se3) allowing for the deconvolution of the surface state response from the bulk. Our measurement of carrier dynamics give an optical mobility exceeding 2100 cm2/V•s at 4 K, indicative of a surface-dominated response, and a scattering lifetime of ~0.18 ps and a carrier density of 6×1012 cm-2 at 4 K for the Bi2Se3 film. The sample was further processed into a Hall bar device using two different etching techniques, a wet chemical etching and Ar+ ion milling, which resulting in a reduced Hall mobility. Even so, the magneto-conductance transport reveals weak antilocalization behavior in our Bi2Se3 sample, consistent with the presence of a single topological surface state mode.
© (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Varun S. Kamboj, Angadjit Singh, Thierry Ferrus, Harvey E. Beere, Liam B. Duffy, Thorsten Hesjedal, Crispin H. W. Barnes, and David A. Ritchie "THz carrier dynamics and magnetotransport study of topological surface states in thin film Bi2Se3", Proc. SPIE 10531, Terahertz, RF, Millimeter, and Submillimeter-Wave Technology and Applications XI, 105310I (23 February 2018); https://doi.org/10.1117/12.2289116
Advertisement
Advertisement
RIGHTS & PERMISSIONS
Get copyright permission  Get copyright permission on Copyright Marketplace
KEYWORDS
Terahertz radiation

Bismuth

Scattering

Thin films

Etching

Magnetism

Wet etching

Back to Top