Nitrogen isotope effects on boron vacancy quantum sensors in hexagonal boron nitride

There has been growing interest in studying hexagonal boron nitride (hBN) for quantum technologies. Here, we investigate nitrogen isotope effects on boron vacancy (V$_\text{B}$) defects, one of the candidates for quantum sensors, in $^{15}$N isotopically enriched hBN synthesized using a metathesis reaction. The Raman shifts are scaled with the reduced mass, consistent with previous work on boron isotope enrichment. We obtain nitrogen isotopic composition-dependent magnetic resonance spectra of V$_\text{B}$ defects and determine the magnitude of the hyperfine interaction parameter of $^{15}$N spin to be 64 MHz. Our investigation provides a design policy for hBNs for quantum sensing.