Topological Surface State Annihilation and Creation in SnTe/Cr_x(BiSb)_2–xTe₃ Heterostructures

Abstract

Topological surface states are a new class of electronic states with novel properties, including the potential for annihilation between surface states from two topological insulators at a common interface. Here, we report the annihilation and creation of topological surface states in the SnTe/Cr x (BiSb) 2−x Te 3 (CBST) heterostructures as evidenced by magneto-transport, polarized neutron reflectometry, and first-principles calculations. Our results show that topological surface states are induced in the otherwise topologically trivial two-quintuple-layers thick CBST when interfaced with SnTe, as a result of the surface state annihilation at the SnTe/CBST interface. Moreover, we unveiled systematic changes in the transport behaviors of the heterostructures with respect to changing Fermi level and thickness. Our observation of surface state creation and annihilation demonstrates a promising way of designing and engineering topological surface states for dissipationless electronics.

Topical Review of Quantum Materials and Heterostructures Studied by Polarized Neutron Reflectometry

“…There is still enormous scope to expand PNR studies on this topic, as only a small portion of the possible topological phases have been explored. For example, only recently, PNR was used for the first time to examine heterostructures consisting of nonmagnetic topological crystalline insulators such as SnTe, in proximity to magnetic TIs, [ 121 ] or simple ferromagnets. [ 122 ] Meanwhile, to the best of our knowledge, there are currently no PNR studies of other important classes of topological materials such as topological semimetals and topological superconductors, or their many combinational heterostructures.…”