Gap states and edge properties of rectangular graphene quantum dot in staggered potential

TL;DR

This paper explores how a staggered potential affects the edge states and magnetic properties of a rectangular graphene quantum dot, revealing potential for spintronic applications.

Contribution

It provides new insights into the edge state behavior and spin degeneracy lifting in graphene quantum dots under staggered potential.

Findings

Gap states are localized on zigzag edges with discrete energy levels.

Spin degeneracy of gap states is lifted by the staggered potential.

Edge magnetic properties depend on spin occupation numbers.

Abstract

We investigate edge properties of a gapful rectangular graphene quantum dot in a staggered potential. In such a system gap states with discrete and closely spaced energy levels exist that are spatially located on the left or right zigzag edge. We find that, although the bulk states outside the energy gap are nearly unaffected, spin degeneracy of each gap state is lifted by the staggered potential. We have computed the occupation numbers of spin-up and -down gap states at various values of the strength of the staggered potential. The electronic and magnetic properties of the zigzag edges depend sensitively on these numbers. We discuss the possibility of applying this system as a single electron spintronic device.