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arXiv · 2507.21475

Lifting spin degeneracy in rhombohedral trilayer graphene for high magnetoresistance applications

Lishu Zhang·Jun Zhou·Jie Yang·Sumit Ghosh·Yi-Ming Zhao·Yuan Ping Feng·Lei Shen
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Abstract

Many exotic properties in rhombohedral (or ABC-stacked) multilayer graphene have recently been reported experimentally. In this Letter, we first reveal the underlying mechanism of spin degeneracy lifting in rhombohedral trilayer graphene. Then, we propose a design concept for all-rhombohedral graphene-based magnetic tunnel junctions (MTJs) by utilizing pristine, back-gated, and top-gated ABC-stacked trilayer graphene, which exhibit semimetallic (conducting), semiconducting (insulating), and half-metallic (ferromagnetic) behavior, respectively. This enables the realization of an "all-in-one" magnetic tunnel junction based entirely on trilayer graphene. This design enables voltage-controlled spintronics (lower power than conventional MTJs) with perfect interfacial matching and sub-nm thickness uniformity across 4-inch wafers. Using first-principles calculations and the non-equilibrium Greens function, we comprehensively study electronic structures and transport properties of these all-graphene MTJs. Furthermore, we demonstrate that their characteristics can be tuned via a perpendicular electric field and electron doping. Our findings offer a new concept for the development of fully graphene-based spintronic devices utilizing the three distinct electronic phases of rhombohedral trilayer graphene.

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Lishu Zhang, Jun Zhou, Jie Yang, Sumit Ghosh, Yi-Ming Zhao, Yuan Ping Feng, Lei Shen. 2025-07-29. Lifting spin degeneracy in rhombohedral trilayer graphene for high magnetoresistance applications. https://arxiv.org/abs/2507.21475

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