Quantum Emission from Coupled Spin Pairs in Hexagonal Boron Nitride

TL;DR

This paper investigates the microscopic origin of quantum emitters in hexagonal boron nitride (hBN), linking optical properties to donor-acceptor pairs through ab initio calculations, and proposes a model for defect qubit identification.

Contribution

It introduces a donor-acceptor pair model explaining optical and magnetic properties of defect qubits in hBN, aiding their identification and optimization.

Findings

Donor-acceptor pairs explain spectral variance and stability.

ODMR signals depend on donor-acceptor configurations and magnetic fields.

The model guides defect qubit identification in hBN.

Abstract

Optically addressable defect qubits in wide band gap materials are favorable candidates for room temperature quantum information processing. The two-dimensional (2D) hexagonal boron nitride (hBN) is an attractive solid state platform with a great potential for hosting bright quantum emitters with quantum memories with leveraging the potential of 2D materials for realizing scalable preparation of defect qubits. Although, room temperature bright defect qubits have been recently reported in hBN but their microscopic origin, the nature of the optical transition as well as the optically detected magnetic resonance (ODMR) have been remained elusive. Here we connect the variance in the optical spectra, optical lifetimes and spectral stability of quantum emitters to donor-acceptor pairs (DAP) in hBN by means of ab initio calculations. We find that DAPs can exhibit ODMR signal for the acceptor counterpart of the defect pair with S=1/2 ground state at non-zero magnetic fields depending on the donor partner. The donor-acceptor pair model and its transition mechanisms provide a recipe towards defect qubit identification and performance optimization in hBN for quantum applications.