Nuclear-induced dephasing and signatures of hyperfine effects in isotopically purified $^{13}$C graphene

TL;DR

This study investigates hyperfine interactions in isotopically purified $^{13}$C graphene, revealing nuclear effects on electron dephasing and spin dynamics through experimental signatures and microwave techniques.

Contribution

It provides experimental evidence of hyperfine effects in $^{13}$C graphene and demonstrates how nuclear spins influence electron dephasing and spin resonance behaviors.

Findings

Signatures of nuclear spins observed in weak localization analysis.

Differences in scattering times between $^{12}$C and $^{13}$C graphene.

Microwave-induced electron spin flips modulate nuclear fields and affect electron Zeeman energy.

Abstract

The hyperfine interaction between the spins of electrons and nuclei is both a blessing and a curse. It can provide a wealth of information when used as an experimental probing technique but it can also be destructive when it acts as a dephasive perturbation on the electronic system. In this work, we fabricated large scale single and multilayer isotopically-purified $^{13}$C graphene Hall bars to search for interaction effects between the nuclear magnetic moments and the electronic system. We find signatures of nuclei with a spin in the analysis of the weak localization phenomenon that shows a significant dichotomy in the scattering times of monolayer $^{12}$C and $^{13}$C graphene close the Dirac point. Microwave-induced electron spin flips were exploited to transfer momentum to the nuclei and build-up a nuclear field. The presence of a very weak nuclear field is encoded in a modulation of the electron Zeeman energy which shifts the energy for resonant absorption and reduces the $g$-factor.