Spin qubit based on the nitrogen-vacancy center analog in a diamond-like compound C₃BN

The nitrogen-vacancy (NV) center in diamond plays important roles in emerging quantum technologies. Currently available methods to fabricate the NV center often involve complex processes such as N implantation. By contrast, in a diamond-like compound C3BN, creating a boron (B) vacancy immediately leads to an NV-center analog. We use the strongly constrained and appropriately normed semilocal density functional - this functional leads to nearly the same zero-phonon line (ZPL) energy as the experiment and as obtained from the more time-consuming hybrid density functional calculations - to explore the potential of this NV-center analog as a novel spin qubit for applications in quantum information processing. We show that the NV-center analog in C3BN possesses many similar properties to the NV center in diamond including a wide bandgap, weak spin-orbit coupling, an energetically stable negatively charged state, a highly localized spin density, a paramagnetic triplet ground state, and strong hyperfine interactions, which are the properties that make the NV center in diamond stand out as a suitable quantum bit (qubit). We also predict that the NV-center analog in C3BN exhibits two ZPL energies that correspond to longer wavelengths close to the ideal telecommunication band for quantum communications. C3BN studied here represents only one example of A3XY (A: group IV element; X/Y: group III/V elements) compounds. We expect many other compounds of this family to have similar NV-center analogs with a wide range of ZPL energies and functional properties, promising to be the new hosts of qubits for quantum technology applications. Furthermore, A3XY compounds often contain group IV elements such as silicon and germanium, so they are compatible with sophisticated semiconductor processing techniques. Our work opens up ample opportunities toward scalable qubit host materials and novel quantum devices.