Quantum Spin - Hall materials hold the promise of revolutionary devices with dissipationless spin currents, but have required cryogenic temperatures owing to small energy gaps. Here, we show theoretically, that a room-temperature regime with a large energy gap can be achieved within a paradigm that exploits the atomic spin-orbit coupling. The new concept is based on a substrate-supported monolayer of a high-Z element, and is experimentally realized as a bismuth honeycomb lattice on top of the insulator SiC(0001). Using scanning tunneling spectroscopy, we detect a gap of order 0.8 eV and conductive edge states consistent with our theory . Our combined theoretical and experimental results [1] demonstrate a systematic path to a Quantum Spin-Hall wide-gap scenario, where the chemical potential resides in the global system gap, ensuring robust edge conductance.

1. F.Reis et.al., Science, June 29 (2017)