  Searching for two-dimensional (2D) realistic materials able to realize
room-temperature quantum spin Hall (QSH) effects is currently a growing field.
Here, we through ab initio calculations to identify arsenene oxide, AsO, as an
excellent candidate, which demonstrates high stability, flexibility, and
tunable spin-orbit coupling (SOC) gaps. In contrast to known pristine or
functionalized arsenene, the maximum nontrivial band gap of AsO reaches 89 meV,
and can be further enhanced to 130 meV under biaxial strain. By sandwiching 2D
AsO between BN sheets, we propose a quantum well in which the band topology of
AsO is preserved with a sizeable band gap. Considering that AsO having fully
oxidized surfaces are naturally stable against surface oxidization and
degradation, this functionality provides a viable strategy for designing
topological quantum devices operating at room temperature.
