Temperature shifts of the resonances of theNV−center in diamond

Significant attention has been recently focused on the realization of high precision nanothermometry using the spin-resonance temperature shift of the negatively charged nitrogen-vacancy (${\mathrm{NV}}^{\ensuremath{-}}$) center in diamond. However, the precise physical origins of the temperature shift is yet to be understood. Here, the shifts of the center's optical and spin resonances are observed and a model is developed that identifies the origin of each shift to be a combination of thermal expansion and electron-phonon interactions. Our results provide insight into the center's vibronic properties and reveal implications for ${\mathrm{NV}}^{\ensuremath{-}}$ thermometry.