Identification of silicon vacancy-related electron paramagnetic resonance centers in 4H SiC

TL;DR

This paper investigates silicon vacancy-related centers in 4H SiC using DFT calculations to identify their electronic and magneto-optical properties, aiming to explain recent ESR signals for quantum technology applications.

Contribution

It introduces V$_ ext{Si}(-)$-related pair defect models and predicts their properties to identify unknown ESR centers in 4H SiC.

Findings

Proposed pair defect models match observed ESR signals.

Predicted optical signals facilitate experimental identification.

Enhanced understanding of defect structures in 4H SiC.

Abstract

The negatively charged silicon vacancy [V$_\text{Si}(-)$] in silicon carbide (SiC) is a paramagnetic and optically active defect in hexagonal SiC. V$_\text{Si}(-)$ defect possesses $S = 3/2$ spin with long spin coherence time and can be optically manipulated even at room temperature. Recently, electron spin resonance signals have been observed besides the signals associated with the V$_\text{Si}(-)$ defects in the 4H polytype of SiC. The corresponding centers share akin properties to those of the V$_\text{Si}(-)$ defects and thus they may be promising candidates for quantum technology applications. However, the exact origin of the new signals is unknown. In this paper we report V$_\text{Si}(-)$-related pair defect models as possible candidates for the unknown centers. We determine the corresponding electronic structures and magneto-optical properties as obtained by density functional theory (DFT) calculations. We propose models for the recently observed electron paramagnetic resonance centers with predicting their optical signals for identification in future experiments.