Strain-based Spin Manipulation on Substitutional Nickel in Silicon Carbide

TL;DR

This study investigates how external strain influences the magnetic states of nickel and chromium dopants in silicon carbide, revealing strain-induced magnetic transitions that could enable new qubit control mechanisms.

Contribution

It demonstrates strain-controlled magnetic phase transitions of Ni dopants in SiC, proposing a novel approach for qubit manipulation.

Findings

Ni in 3C-SiC switches from AFM to FM under strain.

Ni in 4H-SiC remains nonmagnetic regardless of strain.

Cr dopants are stable in magnetic phases under stress.

Abstract

By using the full potential linear augmented plane wave (FP-LAPW) method and full potential local orbital minimum basis (FP-LOMB) method within generalized gradient approximation (GGA), we studied the electronic structures and magnetic properties of nickel and chromium single dopants in polytypes of silicon carbide (SiC). The magnetic phases of defects are found to be strongly dependent on the external stress on the supercell. In 3C-SiC, the Ni single dopant exhibits an anti-ferromagnetic (AFM) to ferromagnetic (FM) transition at a moderate compressive and tensile hydrostatic strain in Si-sub and C-sub cases. In contrast, the Ni single dopant in 4H-SiC is stably in the nonmagnetic phase under external stress. The Cr single dopant is also insensitive to the applied stress but stably in the magnetic phase. This strain controlled magnetic transition makes the Ni single dopant a novel scheme of qubit.