Stability and decoherence analysis of the silicon vacancy in 3C-SiC

TL;DR

This paper investigates the silicon vacancy in 3C-SiC as a potential quantum bit, analyzing its magnetic interactions, coherence properties, and decoherence mechanisms using ab initio calculations and spin dynamics simulations.

Contribution

It provides a detailed ab initio characterization of the silicon vacancy in 3C-SiC and analyzes its coherence decay and decoherence processes in a nuclear spin bath environment.

Findings

Neutral charge state is most favorable for p-doped 3C-SiC.

Identified non exponential coherence decay due to low frequency noise.

Demonstrated the impact of nuclear spin bath on electron spin coherence.

Abstract

We study the silicon vacancy in 3C SiC as a color center of interest in the field of Quantum Technologies, focusing on its magnetic interaction with the SiC nuclear spin bath containing Si29 and C13 nuclei in their natural isotopic concentration. We calculate the system energetic and magnetic properties with ab initio methods based on the Density Functional Theory, identifying the neutral charge state of the silicon vacancy as the most favorable for p doped 3C SiC systems. We thereon evaluate the Free Induction Decay and the Hahn echo sequence on the electron spin interacting with the nuclear spin bath. Here, the Electron Spin Echo Envelope Modulation phenomenon, due to single nuclear spin flipping processes, and the overall decay are highlighted in the context of the Cluster Correlation Expansion theory. We find a non exponential coherence decay, which is a typical feature of solid state qubits subjected to low frequency 1/f noise from the environment.