Nuclear spin-mediated relaxation mechanisms of the $${{\rm{V}}}_{{\rm{B}}}^{-}$$ center in hBN
Year: 2025
Type: article
Abstract: The negatively charged boron vacancy ( $${{\rm{V}}}_{{\rm{B}}}^{-}$$ ) defect in hexagonal boron nitride has recently emerged as a promising spin qubit for sensing due to its high-temperature spin control and versatile integration into van der Waals structures. While extensive experiments have explored their coherence properties, much less is known about the spin relaxation time (T1) and its control parameter dependence. In this work, we develop a parameter-free spin dynamics model based on the cluster expansion technique to investigate T1 relaxation mechanisms at low temperature. Our results reveal that the $${{\rm{V}}}_{{\rm{B}}}^{-}$$ center constitutes a strongly coupled electron spin-nuclear spin core, which necessitates the inclusion of the coherent dynamics and derived memory effects of the three nearest-neighbor nitrogen nuclear spins. Using this framework, this work closely reproduces the experimentally observed T1 time at B = 90 G and further predicts the T1 dependence on external magnetic field in the 0≤B≤2000 G interval, when the spin relaxation is predominantly driven by electron-nuclear and nuclear-nuclear flip-flop processes mediated by hyperfine and dipolar interactions. This study establishes a reliable and scalable approach for describing T1 relaxation in $${{\rm{V}}}_{{\rm{B}}}^{-}$$ centers and offers microscopic insights to support future developments in nuclear-spin-based quantum technologies.
Source: npj Computational Materials
Authors: Chanaprom Cholsuk, Tobias Vogl, Viktor Ivády
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,490
Funders: European Commission, Deutsche Forschungsgemeinschaft, Nemzeti Kutatási Fejlesztési és Innovációs Hivatal, Munich Center for Quantum Science and Technology, Gauss Centre for Supercomputing, HORIZON EUROPE Framework Programme, Leibniz-Gemeinschaft, National Research, Development and Innovation Office, Leibniz-Rechenzentrum
Awards: Twinning to develop ELTE's research and innovation capacity in quantum reservoir computing, G1768993395, G2044776484, G285949800, G2960115771, G3573082562, G390482800, G4229847087, G4447597954, G4710139657, G5018505555, G5768859344, G7310867467, G866891011, EXC 2111: Munich Center for Quantum Science and Technology (MCQST), G8914310889
OpenAlex ID: W4414946548