You are here

The effect of substrate and surface plasmons on symmetry breaking at the substrate interface of the topological insulator Bi2Te3

Publish Year: 2019
Publisher:  Scientific Reportsvolume, 2019, 9, 6147
See this publication
M. Wiesner, R. H. Roberts, J. F. Lin, D. Akinwande, T. Hesjedal, L. B. Duffy, S. Wang, Y. Song, J. Jenczyk, S. Jurga, B. Mróz
A pressing challenge in engineering devices with topological insulators (TIs) is that electron transport is dominated by the bulk conductance, and so dissipationless surface states account for only a small fraction of the conductance. Enhancing the surface-to-volume ratio is a common method to enhance the relative contribution of such states. In thin films with reduced thickness, the confinement results in symmetry-breaking and is critical for the experimental observation of topologically protected surface states. We employ micro-Raman and tip-enhanced Raman spectroscopy to examine three different mechanisms of symmetry breaking in Bi2Te3 TI thin films: surface plasmon generation, charge transfer, and application of a periodic strain potential. These mechanisms are facilitated by semiconducting and insulating substrates that modify the electronic and mechanical conditions at the sample surface and alter the long-range interactions between Bi2Te3 and the substrate. We confirm the symmetry breaking in Bi2Te3 via the emergence of the Raman-forbidden A21u mode. Our results suggest that topological surface states can exist at the Bi2Te3/substrate interface, which is in a good agreement with previous theoretical results predicting the tunability of the vertical location of helical surface states in TI/substrate heterostructures.

Contact | Contact database | RSS | Login
© 2019 CENTRUM NANOBIOMEDYCZNE UAM | ul. Wszechnicy Piastowskiej 3, PL 61614 Poznań, Poland | tel.+48 61 829 67 04.