First-principles Engineering of Charged Defects for Two-dimensional Quantum Technologies

TL;DR

This paper introduces a reliable, parameter-free computational method for accurately predicting defect properties in 2D materials, addressing anisotropic screening issues crucial for quantum technology applications.

Contribution

The authors develop an efficient, parameter-free approach to evaluate quasiparticle defect states and charge transition levels in 2D materials, overcoming previous screening-related challenges.

Findings

Identified $C_BN_V$ as a promising quantum bit candidate.

Provided accurate charge transition levels for defects in monolayer h-BN.

Addressed anisotropic screening issues in 2D materials.

Abstract

Charged defects in 2D materials have emerging applications in quantum technologies such as quantum emitters and quantum computation. Advancement of these technologies requires rational design of ideal defect centers, demanding reliable computation methods for quantitatively accurate prediction of defect properties. We present an accurate, parameter-free and efficient procedure to evaluate quasiparticle defect states and thermodynamic charge transition levels of defects in 2D materials. Importantly, we solve critical issues that stem from the strongly anisotropic screening in 2D materials, that have so far precluded accurate prediction of charge transition levels in these materials. Using this procedure, we investigate various defects in monolayer hexagonal boron nitride (h-BN) for their charge transition levels, stable spin states and optical excitations. We identify $C_BN_V$ (nitrogen vacancy adjacent to carbon substitution of boron) to be the most promising defect candidate for scalable quantum bit and emitter applications.