Controlling spin polarization of gapless states in defected trilayer graphene with a gate voltage

TL;DR

This paper explores how gate voltage can control spin polarization in defected trilayer graphene, revealing that magnetic defects cause hybridization and spin-splitting of gapless states, enabling tunable spin currents.

Contribution

It demonstrates that gate voltage can modulate spin density and currents in defected trilayer graphene with magnetic defects, a novel way to control spintronic properties.

Findings

Magnetic defects hybridize with gap states causing spin-splitting.

Gate voltage alters spin density and Fermi level currents.

Gapless states persist despite structural distortions.

Abstract

Trilayer graphene exhibits valley-protected gapless states when the stacking order changes from ABC to CBA and a gate voltage is applied to outer layers. Some of these states survive strong distortions of the trilayer. For example, they persist when the outer layers are partially devoid yielding a system of two trilayers of different stacking order connected by a strip of a single graphene layer. Here we investigate how these states respond to another perturbation, i.e., the presence of magnetic defects, which we model as pi-vacancies. We show that the gap states hybridize with the defect states and strongly spin-split. More importantly, it is demonstrated that by changing the gate voltage value one can change the spin density of the gap states and the corresponding currents at the Fermi level.