Abstract
The quantum spin Hall effect (QSHE) has formed the seed for contemporary research on topological quantum states of matter. Since its discovery in HgTe/CdTe quantum wells and InAs/GaSb heterostructures, all such systems have so far been suffering from extremely low operating temperatures, rendering any technological application out of reach. We formulate a theoretical paradigm to accomplish the high temperature QSHE in monolayer-substrate heterostructures. Specifically, we explicate our proposal for hexagonal compounds formed by monolayers of heavy group-V elements (As, Sb, Bi) on a SiC substrate. We show how orbital filtering due to substrate hybridization, a tailored multiorbital density of states at low energies, and large spin-orbit coupling can conspire to yield QSH states with bulk gaps of several hundreds of meV. Combined with the successful realization of Bi/SiC (0001), with a measured bulk gap of meV reported previously [F. Reis et al., Science 357, 287 (2017)], our paradigm elevates the QSHE from an intricate quantum phenomenon at low temperatures to a scalable effect amenable to device design and engineering.
2 More- Received 25 July 2018
DOI:https://doi.org/10.1103/PhysRevB.98.165146
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