Exciton and Spin Dynamics for Quantum Defects in Two-dimensional Materials from First-principles

Spin defects in 2D materials such as ultrathin hexagonal boron nitride (hBN) have been found to be promising single-photon emitters and potential candidates for qubits. However, first-principles prediction of accurate defect properties in 2D materials remains challenging, mainly because of the highly anisotropic dielectric screening in 2D materials and strong many body interactions. This work shows how we solve the numerical convergence issues for charged defect properties in 2D materials at both the DFT and many body perturbation theory (GW/Bethe-Salpeter equation), and how we tackle the complex many body interactions including electron-electron, electron-phonon and defect-excitons for the excited state dynamics of spin defects in 2D materials. We are also developing first-principles spin dynamics through Lindblad dynamics for open quantum systems. With our methods, we will design spin defects that have deep defect levels, weak electron-phonon coupling, high radiative recombination rates, and long spin relaxation and coherence time as future materials platforms for quantum information technologies.