  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.
