Electrically-detected single-spin resonance with Quantum Spin Hall edge states

TL;DR

This paper proposes a novel method for electrically detecting single-spin resonance using the edge states of a quantum spin Hall insulator, enabling measurement without applied bias through AC-driven spin dynamics.

Contribution

It introduces a new approach to detect individual spins electrically via QSHI edge states, leveraging spin-momentum locking and AC excitation to generate measurable currents.

Findings

DC current depends on Rabi frequency and spin relaxation times.

The method is feasible with current experimental technology.

No bias voltage needed for detection.

Abstract

Detection is most often the main impediment to reduce the number of spins in paramagnetic resonance experiments. Here we propose a new route to carry out electrically-detected spin resonance of an individual spin, placed at the edge of a quantum spin Hall insulator (QSHI). The edges of a QSHI host a one dimensional electron gas with perfect spin-momentum locking. Therefore, the spin relaxation induced by emission of an electron-hole pair at the edge state of the QSHI can generate current. Here we demonstrate that driving the system with an $AC$ signal, a nonequilibrium occupation can be induced in the absence of applied bias voltage, resulting in a $DC$ measurable current. We compute the $DC$ current as a function of the Rabi frequency $\Omega$, the spin relaxation and decoherence times, $T_1$ and we discuss the feasibility of this experiment with state-of-the-art instrumentation.