Group-IV color centers in diamond (${\mathrm{SiV}}^{–}, {\mathrm{GeV}}^{–}$, and ${\mathrm{SnV}}^{–}$) have emerged as leading solid-state spin-photon interfaces for quantum information processing applications. However, these qubits require cryogenic temperatures to achieve high fidelity operation due to interactions with the thermal phonon environment. In this paper, we (i) derive a detailed model of the decoherence from first-order acoustic phonon processes acting on the spin-orbit fine structure of these color centers, (ii) demonstrate agreement of the model's predicted coherence times with previous measurements, and (iii) identify regimes to suppress phonon-mediated decoherence by changing magnetic field and strain bias to allow higher temperature operation. This methodology enables prediction of decoherence processes in other color centers and solid-state qubit systems coupled to a thermal bath via a parasitic two-level system. By experiment-anchored decoherence models, we facilitate optimizing qubit coherence for specific applications and devices.

• Received 5 October 2023
• Accepted 29 January 2024

DOI:https://doi.org/10.1103/PhysRevB.109.085414