Electron-phonon processes of the silicon-vacancy centre in diamond

TL;DR

This study explores phonon-induced electronic dynamics in the silicon-vacancy center in diamond, measuring optical properties and developing a microscopic model to understand orbital relaxation and coherence for quantum applications.

Contribution

It provides new measurements of optical and relaxation properties of the SiV- center across a wide temperature range and introduces a microscopic model for thermal broadening and phonon interactions.

Findings

Vibronic single-phonon processes govern orbital relaxation at cryogenic temperatures.

Measured optical transition linewidths, wavelengths, and lifetimes from 4-350 K.

Proposed methods to enhance qubit coherence times based on phonon interactions.

Abstract

We investigate phonon induced electronic dynamics in the ground and excited states of the negatively charged silicon-vacancy ($\mathrm{SiV}^-$) centre in diamond. Optical transition line widths, transition wavelength and excited state lifetimes are measured for the temperature range 4-350 K. The ground state orbital relaxation rates are measured using time-resolved fluorescence techniques. A microscopic model of the thermal broadening in the excited and ground states of the $\mathrm{SiV}^-$ centre is developed. A vibronic process involving single-phonon transitions is found to determine orbital relaxation rates for both the ground and the excited states at cryogenic temperatures. We discuss the implications of our findings for coherence of qubit states in the ground states and propose methods to extend coherence times of $\mathrm{SiV}^-$ qubits.