Strongly Anisotropic Spin Relaxation in the Neutral Silicon Vacancy Center in Diamond

TL;DR

This study investigates the spin relaxation properties of the neutral silicon vacancy center in diamond, revealing highly anisotropic T1 relaxation influenced by temperature and magnetic field orientation, with implications for quantum technology applications.

Contribution

It provides the first detailed analysis of anisotropic spin relaxation and temperature dependence of T1 in the neutral silicon vacancy center in diamond.

Findings

T1 decreases rapidly above 20 K following an Orbach process.

T1 is strongly anisotropic, reducing by over three orders of magnitude with magnetic field rotation.

T2 is shorter than T1 but follows the same temperature dependence.

Abstract

Color centers in diamond are a promising platform for quantum technologies, and understanding their interactions with the environment is crucial for these applications. We report a study of spin- lattice relaxation (T1) of the neutral charge state of the silicon vacancy center in diamond. Above 20 K, T1 decreases rapidly with a temperature dependence characteristic of an Orbach process, and is strongly anisotropic with respect to magnetic field orientation. As the angle of the magnetic field is rotated relative to the symmetry axis of the defect, T1 is reduced by over three orders of magnitude. The electron spin coherence time (T2) follows the same temperature dependence but is drastically shorter than T1. We propose that these observations result from phonon-mediated transitions to a low lying excited state that are spin conserving when the magnetic field is aligned with the defect axis, and we discuss likely candidates for this excited state.