Temperature Dependence of the Electron–Nuclear Interaction Parameters of the Boron Vacancy in the hBN Crystal

Abstract

High-spin centers in hexagonal boron nitride are of interest for quantum applications due to their optical and coherent properties. In this work, the behavior of the hyperfine and quadrupole interaction parameters of the negatively charged boron vacancy (\(V^{-}_{B}\)) with nitrogen nuclei in the first and third coordination shells has been investigated using high-frequency (94 GHz, W-band) double electron–nuclear resonance (ENDOR) spectroscopy over a wide temperature range (25–200 K). The ENDOR frequencies governed by the nuclear quadrupole interaction remain nearly constant across the investigated temperature range. This effect is crucial for implementing quantum algorithms involving selective resonant excitation of specific transitions that remain temperature stable. Furthermore, it enables the development of temperature-dependent models for spin-Hamiltonian parameters of the \(V_{B}^{-}\)-center, which are of fundamental importance.