High-precision measurements and first-principles explanation of the temperature-dependent C13 and N14 hyperfine interactions of single NV− centers in diamond at room temperature

Abstract

Revealing the properties of single spin defects in solids is essential for quantum applications based on solid-state systems. However, it is intractable to investigate the temperature-dependent properties of single defects, due to the low precision for single-defect measurements in contrast to defect ensembles. Here we report that the temperature dependence of the Hamiltonian parameters for single negatively charged nitrogen-vacancy centers in diamond at room temperature is precisely measured and the results are in reasonable agreement with first-principles calculations. In particular, the hyperfine interactions with randomly distributed $^{13}\mathrm{C}$ nuclear spins are clearly observed to vary with temperature and the relevant coefficients are measured with hertz-level precision. The temperature-dependent behaviors are attributed to both thermal expansion and lattice vibrations by first-principles calculations. Our results pave the way for taking nuclear spins as more stable thermometers at nanoscale. The methods developed here for high-precision measurements and first-principles calculations can be further extended to other solid-state spin defects.