Quantum spin Hall phase in GeSn heterostructures on silicon

Abstract

Quantum phases of solid-state electron systems can sustain exotic phenomena and a very rich spin physics. We utilize model-solid theory to show that Ge_{1−x}Sn_{x} alloys, an emerging group IV semiconductor, can be engineered into heterostructures that demonstrate a broken-gap alignment. Furthermore, the eight-band k·p method is used to disclose a quantum spin Hall phase in heterojunctions that accommodates the existence of gate-controlled chiral edge states. This proposal introduces a practical silicon-based architecture that spontaneously sustains topological properties, while being compatible with the high-volume manufacture of semiconductor technologies.