Accessing Rashba states in electrostatically gated topological insulator devices

We study the low temperature electrical transport in gated BiSbTe1.25Se1.75/hexagonal-Boron Nitride van der Waals heterostructure devices. Our experiments indicate the presence of Rashba spin-split states confined to the sample surface. While such states have been observed previously in photo-emission spectroscopy and STM experiments, it has not been possible to unambiguously detect them by electrical means and their transport properties remain mostly unknown. We show that these states support highmobility conduction with Hall effectmobilities∼2000 to 3000 cm2/V-s that are paradoxically much larger than themobilities of the topologicalsurface states∼300 cm2/V-s at T  = 2 K. The spin-split nature of these states is confirmed by magneto-resistance measurements that reveal multi-channel weak anti-localization. Our work shows that Rashba spin split states can be electrically accessed in Topological insulators paving the way for futurespintronic applications.

Source: Applied Physics Letters - December 7, 2016 Category: Physics Authors: Abhishek Banerjee, Ananthesh Sundaresh, Kunjalata Majhi, R. Ganesan and P. S. Anil Kumar Source Type: research