Ultimate In-plane Magnetoresistance Ratio of Graphene by Controlling the Gapped Dirac Cone through Pseudospin

TL;DR

This theoretical study demonstrates that by controlling the magnetic alignment of Ni(111) slabs sandwiching graphene, one can achieve a high in-plane magnetoresistance ratio up to 1450%, through manipulation of the gapped Dirac cone via pseudospin.

Contribution

The paper introduces a method to control graphene's Dirac cone gap via pseudospin by magnetic alignment, leading to a significant magnetoresistance effect.

Findings

Antiparallel magnetic alignment opens a bandgap at the Dirac cone.

Parallel alignment preserves the pristine graphene conductance profile.

High magnetoresistance of 1450% can be achieved with optimized Ni(111) slab width.

Abstract

$\require{mediawiki-texvc}$ A theoretical study is presented on the in-plane conductance of graphene that is partially sandwiched by Ni(111) slabs with a finite size and atom-scale width of $\approx12.08 \AA$. In the sandwiched part, the gapped Dirac cone of graphene can be controlled via pseudospin by changing the magnetic alignment of the Ni(111) slabs. When the magnetic moments of the upper and lower Ni(111) slabs have antiparallel and parallel configurations, the bandgap at the Dirac cone is open and closed, respectively. The transmission probability calculation for the in-plane conductance of the system indicated that the antiparallel configuration would result in nearly zero conductance of $E-E_F=0.2$ eV. In the parallel configuration, the transmission probability calculation indicated that the system would have a profile similar to that of pristine graphene. A comparison of the transmission probabilities of the antiparallel and parallel configurations indicated that a high magnetoresistance of $1450\%$ could be achieved. An ultimate magnetoresistance can be expected if the Ni(111) slab widths are increased to the nanometer scale.