Quantum spin Hall phase in GeSn heterostructures on silicon

TL;DR

This paper proposes a silicon-compatible GeSn heterostructure that can host quantum spin Hall states, enabling integrated topological quantum devices with potential for scalable manufacturing.

Contribution

It introduces a practical GeSn-based heterostructure design capable of supporting topological phases compatible with silicon technology.

Findings

GeSn alloys can form junctions with broken gap alignment.

Predicted quantum phase transition supports gate-controlled chiral edge states.

Potential for integrated circuits with topological quantum functionalities.

Abstract

Quantum phases of solid-state electron systems look poised to sustain exotic phenomena and a very rich spin physics. We propose a practical silicon-based architecture that spontaneously sustains topological properties, while being fully compatible with the high-volume manufacturing capabilities of modern microelectronic foundries. Here we show how Ge1-xSnx alloys, an emerging group IV semiconductor, can be engineered into junctions that demonstrate a broken gap alignment. We predict such basic building block undergo a quantum phase transition that can elegantly accommodate the existence of gate-controlled chiral edge states directly on Si. This will enable tantalizing prospects for designing integrated circuits hosting quantum spin hall insulators and advanced topological functionalities.