Linear scaling between momentum and spin scattering in graphene

Abstract

Spin transport in graphene carries the potential of a long spin-diffusion length at room temperature. However, extrinsic relaxation processes limit the current experimental values to $1--2\text{ }\ensuremath{\mu}\text{m}$. We present Hanle spin precession measurements in gated lateral spin valve devices in the low to high (up to ${10}^{13}\text{ }{\text{cm}}^{\ensuremath{-}2}$) carrier density range of graphene. A linear scaling between the spin-diffusion length and the diffusion coefficient is observed. We measure nearly identical spin- and charge diffusion coefficients indicating that electron-electron interactions are relatively weak and transport is limited by impurity potential scattering. When extrapolated to the maximum carrier mobilities of $2\ifmmode\times\else\texttimes\fi{}{10}^{5}\text{ }{\text{cm}}^{2}/\text{Vs}$, our results predict that a considerable increase in the spin-diffusion length should be possible.