Excited-State Optically Detected Magnetic Resonance of Spin Defects in Hexagonal Boron Nitride
Zhao Mu, Hongbing Cai, Disheng Chen, Jonathan Kenny, Zhengzhi Jiang, Shihao Ru, Xiaodan Lyu, Teck Seng Koh, Xiaogang Liu, Igor Aharonovich, Weibo Gao
Abstract
Negatively charged boron vacancy (V_{B}^{-}) centers in hexagonal boron nitride (h-BN) are promising spin defects in a van der Waals crystal. Understanding the spin properties of the excited state (ES) is critical for realizing dynamic nuclear polarization. Here, we report zero-field splitting in the ES of D_{ES}=2160 MHz and its associated optically detected magnetic resonance (ODMR) contrast of 12% at cryogenic temperature. In contrast to nitrogen vacancy (NV^{-}) centers in diamond, the ODMR contrast of V_{B}^{-} centers is more prominent at cryotemperature than at room temperature. The ES has a g factor similar to the ground state. The ES photodynamics is further elucidated by measuring the level anticrossing of the V_{B}^{-} defects under varying external magnetic fields. Our results provide important information for utilizing the spin defects of h-BN in quantum technology.