DC Magnetic Field Sensitivity Optimization of Spin Defects in Hexagonal Boron Nitride.

Zhou, Feifei; Jiang, Zhengzhi; Liang, Haidong; Ru, Shihao; Bettiol, Andrew A; Gao, Weibo · Nano Lett · 2023

basic_science · Level V

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Abstract

Spin defects existing in van der Waals materials attract wide attention thanks to their natural advantages for <i>in situ</i> quantum sensing, especially the negatively charged boron vacancy (V<sub>B</sub><sup>-</sup>) centers in hexagonal boron nitride (<i>h</i>-BN). Here we systematically investigate the laser and microwave power broadening in continuous-wave optically detected magnetic resonance (ODMR) of the V<sub>B</sub><sup>-</sup> ensemble in <i>h</i>-BN, by revealing the behaviors of ODMR contrast and line width as a function of the laser and microwave powers. The experimental results are well explained by employing a two-level simplified model of ODMR dynamics. Furthermore, with optimized power, the DC magnetic field sensitivity of V<sub>B</sub><sup>-</sup> ensemble is significantly improved up to 2.87 ± 0.07 μT/<math xmlns="http://www.w3.org/1998/Math/MathML"><msqrt><mrow><mi>H</mi><mi>z</mi></mrow></msqrt></math>. Our results provide important suggestions for further applications of V<sub>B</sub><sup>-</sup> centers in quantum information processing and ODMR-based quantum sensing.