  Atomically thin topological materials are attracting growing attention for
their potential to radically transform classical and quantum electronic device
concepts. Amongst them is the quantum spin Hall (QSH) insulator - a
two-dimensional state of matter that arises from an interplay of topological
band inversion and strong spin-orbit coupling, with large tunable bulk band
gaps up to 800meV and gapless, one-dimensional edge states. Reviewing recent
advances in materials science and engineering alongside theoretical
description, this article surveys the QSH materials library with focus on their
prospects for QSH-based device applications. In particular, this review
discusses theoretical predictions of non-trivial superconducting pairing in the
QSH state towards Majorana based topological quantum computing - the next
frontier in QSH materials research.
