Spin Manipulation in Graphene by Chemically-Induced Sublattice Pseudospin Polarization

TL;DR

This paper demonstrates that chemical impurities like fluorine ad-atoms can induce sublattice pseudospin polarization in graphene, enabling tunable spin lifetimes from picoseconds to nanoseconds for advanced spintronic applications.

Contribution

It introduces a novel method of manipulating spin in graphene through chemically induced sublattice pseudospin polarization without magnetic moments.

Findings

Impurities cause long-range pseudospin polarization affecting spin transport.

Spin lifetime can be electrostatically tuned over three orders of magnitude.

Chemical engineering of spin properties in graphene is feasible without magnetic impurities.

Abstract

Spin manipulation is one of the most critical challenges to realize spin-based logic devices and spintronic circuits. Graphene has been heralded as an ideal material to achieve spin manipulation but so far new paradigms and demonstrators are limited. Here we show that certain impurities such as fluorine ad-atoms, which locally break sublattice symmetry without the formation of strong magnetic moment, could result in a remarkable variability of spin transport characteristics. The impurity resonance level is found to be associated with a long range sublattice pseudospin polarization, which by locally decoupling spin and pseudospin dynamics, provokes a huge spin lifetime electron-hole asymmetry. In the dilute impurity limit, spin lifetimes could be tuned electrostatically from hundred picoseconds to several nanoseconds, providing a protocol to chemically engineer an unprecedented spin device functionality.