Low Temperature Studies of Charge Dynamics of Nitrogen-Vacancy Defect in Diamond

TL;DR

This study investigates the charge state switching of nitrogen-vacancy centers in diamond at low temperatures, revealing mechanisms that enhance their stability and utility in quantum information processing.

Contribution

It experimentally demonstrates charge state conversion of NV centers at cryogenic temperatures and discusses mechanisms for ionization and recovery, improving understanding for quantum applications.

Findings

NV- to NV0 conversion scales quadratically with power

Resonant excitation can recover NV- charge state

Charge dynamics understanding aids quantum information processing

Abstract

In this paper, we study the photoinduced switching of the nitrogen-vacancy (NV) center between two different charge states - negative (NV-) and neutral (NV0) at liquid helium temperature. The conversion of NV- to NV0 on a single defect is experimentally proven and its rate scales quadratically with power under resonant excitation. In addition, we found that resonant excitation of the neutral NV changes the charge state, recovering its negative configuration. This type of conversion significantly improves spectral stability of NV- defect and allows high fidelity initialization of the spin qubit. A possible mechanism for ionization and recovery of the NV- defect is discussed. This study provides better understanding of the charge dynamics of the NV center, which is relevant for quantum information processing based on NV defect in diamond.