Spin decontamination for magnetic dipolar coupling calculations: Application to high-spin molecules and solid-state spin qubits

Timur Biktagirov,Wolf Gero Schmidt,Uwe Gerstmann

doi:10.1103/physrevresearch.2.022024

Timur Biktagirov, Wolf Gero Schmidt + Show 1 more

Open Access

https://doi.org/10.1103/physrevresearch.2.022024

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Journal: Physical review research	Publication Date: Apr 30, 2020
Citations: 9	License type: CC BY 4.0

Affiliation: Paderborn University

Abstract

An accurate description of the two-electron density, crucial for magnetic coupling in spin systems, provides in general a major challenge for density functional theory calculations. It affects, e.g., the calculated zero-field splitting (ZFS) energies of spin qubits in semiconductors that frequently deviate significantly from experiment. In the present work (i) we propose an efficient and robust strategy to correct for spin contamination in both extended periodic and finite-size systems, (ii) verify its accuracy using model high-spin molecules, and finally (iii) apply the methodology to calculate accurate ZFS of spin qubits (NV$^-$ centers, divacancies) in diamond and silicon carbide. The approach is shown to reduce the dependence on the used exchange-correlation functional to a minimum.

Highlights

An accurate description of the two-electron density, crucial for magnetic coupling in spin systems, provides in general a major challenge for density functional theory calculations
In the present work, (i) we propose an efficient and robust strategy to correct for spin contamination in both extended periodic and finite-size systems, (ii) verify its accuracy using model high-spin molecules, and (iii) apply the methodology to calculate accurate zero-field splitting (ZFS) of spin qubits (NV− centers, divacancies) in diamond and silicon carbide
The effects of spin contamination are well known for molecular systems, they have scarcely been considered for solids

Summary

Introduction

Spin decontamination for magnetic dipolar coupling calculations: Application to high-spin molecules and solid-state spin qubits An accurate description of the two-electron density, crucial for magnetic coupling in spin systems, provides in general a major challenge for density functional theory calculations. In the present work, (i) we propose an efficient and robust strategy to correct for spin contamination in both extended periodic and finite-size systems, (ii) verify its accuracy using model high-spin molecules, and (iii) apply the methodology to calculate accurate ZFS of spin qubits (NV− centers, divacancies) in diamond and silicon carbide.

Results

Conclusion