Robust Subthermionic Topological Transistor Action via Antiferromagnetic Exchange

Abstract

The topological quantum field-effect transition in buckled two-dimensional-Xenes can potentially enable subthermionic transistor operation coupled with a dissipationless on-state conduction. We investigate realistic device structures that exploit the quantum field-effect transition between the dissipationless topological phase and the band-insulator phase. We find that the previously considered dual-gate structure is disadvantageous, leading to a near doubling of the subthreshold swing. However, we identify a single-gate strategy capable of overcoming the thermionic limit at the cost of sacrificing the dissipationless on-state conduction. By introducing an out-of-plane antiferromagnetic exchange in the material via proximity coupling, we exploit transitions between the quantum spin-valley Hall and the spin quantum anomalous Hall phase, which restore the topological robustness of the on state while simultaneously surpassing the thermionic limit. Our work thus outlines a realistic pathway to topological transistors that can overcome Boltzmann's tyranny while preserving topological robustness.