Theory of spin-polarized current flow through a localized spin triplet state

TL;DR

This paper develops a quantum-coherent formalism for spin-polarized current through a spin triplet defect, predicting magnetoresistance signatures that reveal the defect's spin properties and enable electrical spin polarization.

Contribution

It introduces a novel formalism for analyzing spin-polarized current through spin triplet states, highlighting potential for electrically initializing spin-triplet qubits.

Findings

Distinct magnetoresistance signatures for different spin triplet states

Ability to electrically polarize and initialize spin-triplet qubits

Identification of spin triplet orientation via magnetoresistance

Abstract

We derive a formalism describing quantum-coherent features of spin-polarized charge current through a partially-polarized spin triplet defect in a $\textit{transverse}$ magnetic field. We predict distinct few-milli-tesla-dc magnetoresistance signatures that identify a $\textit{single}$ spin-triplet center's character and reveal the orientation of the spin triplet's zero-field splitting axis relative to the magnetic contact's polarization. For example, in 4H-SiC the single $(hh)$, $(kk)$, $(hk)$, and $(kh)$ divacancies are all distinct. Spin-polarized current flow efficiently polarizes the spin, potentially electrically initializing spin-triplet-based qubits.