Spin injection based on the spin gapless semiconductor(SGS)/semiconductor heterostructures

TL;DR

This paper proposes using spin gapless semiconductors as spin injectors to overcome conductivity mismatch issues in spintronics, demonstrating high spin polarization and potential for long spin diffusion lengths through first-principles calculations.

Contribution

It introduces a novel spin injection scheme replacing metallic injectors with spin gapless semiconductors, reducing conductivity mismatch and maintaining high spin polarization.

Findings

High spin polarization at interfaces in Mn2CoAl/Fe2VAl and Mn2CoAl/GaAs systems.

Potential for long spin diffusion length in Mn2CoAl/GaAs.

Pronounced dip in majority-spin DOS indicating fast carrier transport.

Abstract

Spin injection efficiency based on conventional ferromagnet (or half-metallic ferromagnet) /semiconductor is greatly limited by the Schmidt obstacle due to conductivity mismatch, here we proposed that by replacing the metallic injectors with spin gapless semiconductors can significantly reduce the conductive mismatch while conserve high spin polarization. By performing first principles calculations based on superlattice structure, we have studied the representative system of Mn2CoAl/semiconductor spin injector scheme. The results showed that high spin polarization were maintained at the interface in systems of Mn2CoAl/Fe2VAl constructed with (100) interface and Mn2CoAl/GaAs with (110) interface, and the latter is expected to possess long spin diffusion length. Inherited from the spin gapless feature of Mn2CoAl, a pronounced dip was observed around the Fermi level in the majority-spin DOS in both systems, suggesting fast transport of the low-density carriers.