Spin-coherence characterization of boron vacancy defects in hexagonal boron nitride with broadband microwave pulses
Yuki Nakamura, Takuya Iwasaki, Shu Nakaharai, Shinichi Ogawa, Yukinori Morita + 4 more
TLDR
This paper characterizes the spin coherence of boron vacancy defects in hBN using broadband microwave pulses, revealing T2* and T2 values.
Key contributions
- Achieved sub-GHz Rabi oscillations of VB- defects in hBN using a gold wire setup.
- Measured spin coherence time T2* = 13.8 ns via Ramsey interference.
- Determined spin coherence time T2 = 108.7 ns and stretch factor α=1.25 using Hahn echo.
- Developed an effective method for coherence evaluation in van der Waals thin films with broad linewidths.
Why it matters
This study experimentally clarifies the spin coherence properties of VB- defects, which are promising for nanoscale quantum sensing. The developed method offers a robust way to evaluate coherence in van der Waals thin films, advancing quantum material characterization.
Original Abstract
Negatively charged boron vacancy (VB-) defects in hexagonal boron nitride (hBN) are promising for nanoscale-proximity quantum sensing. To evaluate their performance, it is important to characterize the spin coherence times T2* and T2. In this study, we realized sub-GHz Rabi oscillations of VB- using an isotopically enriched hBN thin film directly stamped onto a narrow gold wire. Using these strong microwave pulses, we performed Ramsey interference and Hahn echo measurements. The Ramsey interference signal showed Gaussian-like decay, yielding T2* = 13.8 ns. The Hahn echo measurement gave T2 = 108.7 ns and a stretch factor of α= 1.25. These results experimentally clarify the spin coherence properties of VB- and provide an effective method for evaluating the coherence of spin defects in van der Waals thin films with broad resonance linewidths.
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