Highly spin-polarized conducting state at the interface between non-magnetic band insulators: LaAlO3/FeS2 (001)

TL;DR

This study uses first-principles calculations to show that an interface between two non-magnetic insulators, LaAlO3 and FeS2, can host a highly spin-polarized conducting state, promising for spintronics.

Contribution

It demonstrates the creation of a spin-polarized conducting interface between non-magnetic insulators using first-principles density functional theory.

Findings

A localized surface state exists on FeS2 (001) surface.

Electron transfer from LaAlO3 induces conduction at the interface.

The interface exhibits a highly spin-polarized conducting state.

Abstract

First-principles density functional calculations demonstrate that a spin-polarized two-dimensional conducting state can be realized at the interface between two non-magnetic band insulators. The (001) surface of the diamagnetic insulator FeS2 (pyrite) supports a localized surface state deriving from Fe d-orbitals near the conduction band minimum. The deposition of a few unit cells of the polar perovskite oxide LaAlO3 leads to electron transfer into these surface bands, thereby creating a conducting interface. The occupation of these narrow bands leads to an exchange splitting between the spin sub-bands, yielding a highly spin-polarized conducting state distinct from the rest of the non-magnetic, insulating bulk. Such an interface presents intriguing possibilities for spintronics applications.