Spin Relaxation in Single Layer Graphene with Tunable Mobility

TL;DR

This study investigates the impact of charged impurity scattering on spin relaxation in single layer graphene, finding that mobility can be tuned without affecting spin lifetimes, which remain unaffected by charged impurities.

Contribution

The paper introduces a method to tune graphene's mobility independently of charged impurity effects, clarifying their role in spin relaxation.

Findings

Mobility in graphene can be increased without reducing spin lifetime.

Charged impurities significantly affect mobility but not spin relaxation.

Spin lifetimes remain long despite variations in impurity scattering.

Abstract

Graphene is an attractive material for spintronics due to theoretical predictions of long spin lifetimes arising from low spin-orbit and hyperfine couplings. In experiments, however, spin lifetimes in single layer graphene (SLG) measured via Hanle effects are much shorter than expected theoretically. Thus, the origin of spin relaxation in SLG is a major issue for graphene spintronics. Despite extensive theoretical and experimental work addressing this question, there is still little clarity on the microscopic origin of spin relaxation. By using organic ligand-bound nanoparticles as charge reservoirs to tune mobility between 2700 and 12000 cm2/Vs, we successfully isolate the effect of charged impurity scattering on spin relaxation in SLG. Our results demonstrate that while charged impurities can greatly affect mobility, the spin lifetimes are not affected by charged impurity scattering.