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 may be achievable within a paradigm that exploits the atomic spin-orbit coupling. The concept is based on a substrate-supported monolayer of a high–atomic number element and is experimentally realized as a bismuth honeycomb lattice on top of the insulating silicon carbide substrate SiC(0001). Using scanning tunneling spectroscopy, we detect a gap of ~0.8 electron volt and conductive edge states consistent with theory. Our combined theoretical and experimental results demonstrate a concept for a quantum spin Hall wide-gap scenario, where the chemical potential resides in the global system gap, ensuring robust edge conductance.

量子自旋霍尔材料有望实现具有无耗散自旋电流的革命性器件，但由于能隙较小，因此需要低温。在这里，我们从理论上证明，在利用原子自旋轨道耦合的范式内，可以实现具有大能隙的室温状态。该概念基于高原子序数的衬底支撑单分子层，并通过实验实现为绝缘碳化硅衬底SiC（0001）顶部的铋蜂窝状晶格。使用扫描隧道光谱法，我们检测到〜0.8电子伏特的间隙和符合理论的导电边缘态。我们的理论和实验结果相结合，证明了量子自旋霍尔宽能隙情形的概念，其中化学势位于整体系统间隙中，