Demonstration of the ODMR activity of the telecom range ClV center in SiC: a wavefunction theory analysis

TL;DR

This study uses advanced wavefunction theory to analyze the electronic structure of the ClV defect in SiC, demonstrating its potential as a telecom-range spin qubit suitable for quantum networks.

Contribution

It provides the first detailed wavefunction-based analysis of the ClV center, confirming its suitability for ODMR and quantum information applications in 4H-SiC.

Findings

ClV center exhibits optically addressable spin states

The defect shows potential for telecom-range quantum communication

Theoretical estimates support experimental observations

Abstract

Recently, density functional theory-based high-throughput screening of point defects in 4H-SiC revealed the positively charged chlorine-vacancy (ClV) defect to be a promising quantum bit candidate emitting at telecom wavelengths, with an electronic structure analogous to the well-known NV center in diamond. Furthermore, recent infrared photoluminescence (PL) measurements on chlorine-implanted 4H-SiC have revealed new PL lines associated with the ClV defect. While the defect possesses a high-spin ground state, there is a lack of evidence of optically detected magnetic resonance (ODMR), a key ingredient for optical spin initialization and readout. In this Letter, we employ a multireference wavefunction-based quantum chemistry method, specifically, second-order perturbation theory (NEVPT2) on top of a defect-localized many-body wavefunction (CASSCF), to explore the many-body electronic structure of the ClV center. We estimate photoluminescence, internal conversion, and intersystem crossing rates to investigate the possibility of spin polarization and ODMR activity. Our findings establish the ClV center in 4H-SiC as an optically addressable spin qubit with fiber optics compatibility in the technologically mature 4H-SiC host material, enabling the development of large-scale quantum networks.