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arXiv · 2111.10855

Excited-state spin-resonance spectroscopy of V$_\text{B}^-$ defect centers in hexagonal boron nitride

Nikhil Mathur·Arunabh Mukherjee·Xingyu Gao·Jialun Luo·Brendan A. McCullian·Tongcang Li·A. Nick Vamivakas·Gregory D. Fuchs
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Abstract

The recently discovered spin-active boron vacancy (V$_\text{B}^-$) defect center in hexagonal boron nitride (hBN) has high contrast optically-detected magnetic resonance (ODMR) at room-temperature, with a spin-triplet ground-state that shows promise as a quantum sensor. Here we report temperature-dependent ODMR spectroscopy to probe spin within the orbital excited-state. Our experiments determine the excited-state spin Hamiltonian, including a room-temperature zero-field splitting of 2.1 GHz and a g-factor similar to that of the ground-state. We confirm that the resonance is associated with spin rotation in the excited-state using pulsed ODMR measurements, and we observe Zeeman-mediated level anti-crossings in both the orbital ground- and excited-state. Our observation of a single set of excited-state spin-triplet resonance from 10 to 300 K is consistent with an orbital-singlet, which has consequences for understanding the symmetry of this defect. Additionally, the excited-state ODMR has strong temperature dependence of both contrast and transverse anisotropy splitting, enabling promising avenues for quantum sensing.

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Nikhil Mathur, Arunabh Mukherjee, Xingyu Gao, Jialun Luo, Brendan A. McCullian, Tongcang Li, A. Nick Vamivakas, Gregory D. Fuchs. 2021-11-21. Excited-state spin-resonance spectroscopy of V$_\text{B}^-$ defect centers in hexagonal boron nitride. https://doi.org/10.1038/s41467-022-30772-z

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