Carbon and vacancy centers in hexagonal boron nitride

TL;DR

This study uses density functional theory to analyze defect formation in hexagonal boron nitride, revealing how vacancy and substitutional defects stabilize through electron pairing, influencing electronic properties.

Contribution

It provides a microscopic understanding of defect formation mechanisms and the electronic stabilization processes in hexagonal boron nitride.

Findings

Electron pairing stabilizes defect complexes.

Defect complexes modify electronic interactions.

Inheritance of electronic properties in defect combinations.

Abstract

Creation of defect with predetermined optical, chemical and other characteristics is a powerful tool to enhance the functionalities of materials. Herewith, we utilize density functional theory to understand the microscopic mechanisms of formation of defects in hexagonal boron nitride based on vacancies and substitutional atoms. Through in-depth analysis of the defect-induced band structure and formation energy in varying growth conditions, we uncovered a dominant role of interdefect electron paring in stabilization of defect complexes. The electron reorganization modifies the exchange component of the electronic interactions which dominates over direct Coulomb repulsion or structural relaxation effects making the combination of acceptor- and donor-type defect centers energetically favorable. Based on an analysis of a large number of defect complexes we develop a simple picture of the inheritance of electronic properties when individual defects are combined together to form more complex centers.