Suppression of the optical linewidth and spin decoherence of a quantum spin center in a $p$$-$$n$ diode

TL;DR

This paper develops a quantitative theory linking charge fluctuation noise suppression in p-n diodes to reductions in optical linewidth and spin decoherence of quantum spin centers, providing insights into defect depth and decoherence dynamics.

Contribution

It introduces a comprehensive model connecting electric fields and voltage to defect behavior, and describes the spin decoherence process with a spin-1 formalism, predicting noise suppression effects.

Findings

Charge fluctuation noise suppression reduces optical linewidth.

Bi-exponential decoherence process for spin centers.

Defect depth can be inferred from threshold voltage.

Abstract

We present a quantitative theory of the suppression of the optical linewidth due to charge fluctuation noise in a ${p}$$-$${n}$ diode, recently observed in Anderson et al., Science 366, 1225 (2019). We connect the local electric field with the voltage across the diode, allowing for the identification of the defect depth from the experimental threshold voltage. Furthermore, we show that an accurate description of the decoherence of such spin centers requires a complete spin$-$1 formalism that yields a bi-exponential decoherence process, and predict how reduced charge fluctuation noise suppresses the spin center's decoherence rate.