Gate-tunable synthetic antiferromagnetism with nonrelativistic spin splitting in a graphene/MnS/graphene heterostructure

TL;DR

This paper proposes a graphene-based heterostructure with MnS that can be tuned with a gate to produce nonrelativistic spin splitting, enabling new spintronic devices with observable magnetoresistance effects.

Contribution

It introduces a novel gate-tunable synthetic antiferromagnet using graphene and MnS, demonstrating nonrelativistic spin splitting through ab initio and tight-binding models.

Findings

Gate-tuning breaks graphene equivalence, inducing opposite ferromagnetic exchange.

Nonrelativistic spin splitting dominates over relativistic effects.

Observable conductance dips and giant magnetoresistance near the Fermi level.

Abstract

We propose encapsulating type-A antiferromagnetic semiconductors between graphene layers to realize a gate-tunable synthetic antiferromagnet with nonrelativistic spin splitting, enabling efficient spintronic transport via graphene. Ab initio calculations and tight-binding models of graphene/MnS/graphene heterostructure reveal that gate-tuning of the heterostructure breaks top/bottom graphene equivalence, inducing opposite ferromagnetic proximity exchange that lifts spin degeneracy to yield nonrelativistic spin splitting at the Fermi level, dominating over relativistic effects. The induced effects manifest as conductance dips in spin-resolved transport through proximitized graphene nanoribbons, observable as giant magnetoresistance within a narrow energy window around the Fermi level. Our graphene/type-A antiferromagnetic heterostructure, a readily synthesizable platform incorporating antiferromagnets with nonrelativistic spin splitting, pave the way for gate-manipulated, low-dimensional antiferromagnetic devices.