Nitrogen-Vacancy Singlet-Manifold Ionization Energy

Abstract

The singlet states of the negatively charged nitrogen-vacancy centers in diamond play a key role in its optical spin control and readout. In this work, the hitherto unknown ionization energy of the singlet is measured experimentally and found to be in the range 1.91--2.25 eV. This is obtained by analyzing photoluminescence measurements incorporating spin control and nitrogen-vacancy charge state differentiation, along with simulations based on the nitrogen-vacancy's master equation. This work establishes a protocol for a more accurate estimate of this ionization energy, which can possibly lead to improved readout methods.