Spintronics and Pseudospintronics in Graphene and Topological Insulators

TL;DR

This paper reviews the distinct spintronic and pseudospintronic properties of graphene and topological insulators, focusing on spin relaxation, spin polarization, magnetic responses, and pseudospin phenomena related to their Dirac electron systems.

Contribution

It provides a comparative overview of spin and pseudospin phenomena in graphene and topological insulators, highlighting recent advances and differences due to their spin-orbit coupling strengths.

Findings

Graphene exhibits long spin relaxation times due to weak spin-orbit coupling.

Topological insulators can achieve large current-induced spin polarizations.

Bilayer graphene shows pseudospin analogs of giant magnetoresistance.

Abstract

The two-dimensional electron systems in graphene and in topological insulators are described by massless Dirac equations. Although the two systems have similar Hamiltonians, they are polar opposites in terms of spin-orbit coupling strength. We briefly review the status of efforts to achieve long spin relaxation times in graphene with its weak spin-orbit coupling, and to achieve large current-induced spin polarizations in topological-insulator surface states that have strong spin-orbit coupling. We also comment on differences between the magnetic responses and dilute-moment coupling properties of the two systems, and on the pseudospin analog of giant magnetoresistance in bilayer graphene.