Electrical Control of Optically Active Single Spin Qubits in ZnSe

TL;DR

This paper demonstrates electrical control over single spin qubits in ZnSe quantum wells, enabling tuning of emission energy and reduction of spectral noise, which enhances their potential for quantum information applications.

Contribution

It introduces a method to electrically tune and stabilize single donor qubits in ZnSe, improving optical coherence and addressability by suppressing charge noise.

Findings

Electrical field induces a large Stark shift exceeding inhomogeneous linewidth

Application of the field reduces optical linewidth and spectral wandering

A trap dynamics model explains charge noise suppression mechanism

Abstract

Electrons bound to shallow donors in ZnSe quantum wells are promising candidates for optically addressable spin qubits and single-photon sources. However, their optical coherence and indistinguishability are often limited by spectral broadening arising from charge fluctuations in the local environment. Here, we report electrical control of single donor qubits in ZnSe quantum wells. The applied field induces a DC Stark shift that tunes the emission energy over a range exceeding 30 times the inhomogeneous linewidth, effectively compensating for emitter-to-emitter variations. Concurrently, the field stabilizes trap occupancy, yielding a twofold reduction in optical linewidth and the suppression of spectral wandering. A statistical model based on trap dynamics qualitatively reproduces these observations and elucidates the mechanism of field-assisted charge noise suppression. Our results identify electrical control as a versatile pathway to significantly improve optical and spin addressability.