Effects of hydrostatic compression and tension on silicon-vacancy centers in diamond

Hydrostatic deformation is an effective approach for tuning the quantum properties of color centers in diamond, with significant implications for quantum sensing, computing, and communication. Compared to the widely studied nitrogen-vacancy (NV) centers, silicon-vacancy (SiV) centers exhibit more than a tenfold increase in coherent photon emission. In this work, we investigate the effects of hydrostatic pressure and tension on the SiV center in diamond using first-principles calculations with the r2SCAN meta-GGA (Generalized Gradient Approximation) functional. We demonstrate that under hydrostatic tension corresponding to an isotropic expansion exceeding 4%, the SiV center undergoes spontaneous symmetry breaking from the inversion-symmetric D3d structure to the asymmetric C3v configuration, similar to that of the NV center. Within the hydrostatic compression and tension range corresponding to isotropic deformations of −8%–4%, the optical properties and hyperfine parameters of the SiV center change monotonically, indicating promising potential for pressure- or deformation-sensing applications. A microscopic explanation of these trends is provided from an electronic structure perspective. The r2SCAN meta-GGA functional shows high accuracy in calculating hyperfine parameters, in agreement with experimental results. This study enhances our understanding of the optical properties and hyperfine interactions of SiV defects in diamond, laying the groundwork for their potential use in hydrostatic pressure or strain sensing applications.