Recent advances of defect-induced spin and valley polarized states in graphene

TL;DR

This paper reviews recent STM studies on how atomic-scale defects in graphene induce spin and valley polarized states, offering insights into potential spintronics and valleytronics applications.

Contribution

It provides a comprehensive overview of recent experimental advances in defect-induced spin and valley polarization in graphene using STM techniques.

Findings

Atomic defects can lift degeneracies in graphene.

STM reveals localized spin and valley polarized states.

Defect types include vacancies, dopants, and chemisorbed atoms.

Abstract

Electrons in graphene have fourfold spin and valley degeneracies owing to the unique bipartite honeycomb lattice and an extremely weak spin-orbit coupling, which can support a series of broken symmetry states. Atomic-scale defects in graphene are expected to lift these degenerate degrees of freedom at the nanoscale, and hence, lead to rich quantum states, highlighting promising directions for spintronics and valleytronics. In this article, we mainly review the recent scanning tunneling microscopy (STM) advances on the spin and/or valley polarized states induced by an individual atomic-scale defect in graphene, including a single-carbon vacancy, a nitrogen-atom dopant, and a hydrogen-atom chemisorption. Lastly, we give a perspective in this field.