Jonah Nagura, Mykyta Onizhuk, Giulia Galli
NV centers in diamond are promising quantum sensors, but when placed only nanometers below the host surface they are disturbed by every microscopic detail of the surface and they quickly lose their coherence properties. First principles atomistic modeling combined with spin dynamics simulations show that the culprit is not just the type of spins living at the surface, but how they move: surface noise is dynamical. Termination chemistry and facet orientation do matter, but surface-electron relaxation and hopping dominate the coherence of shallow NVs.