Long-distance spin transport in high-mobility graphene on hexagonal boron nitride

TLDR

Spin transport was measured in high‑mobility (up to 40 000 cm² V⁻¹ s⁻¹) single‑layer graphene on hexagonal boron nitride. Spin transport was observed over 20 µm at room temperature, the longest reported for graphene, with relaxation lengths up to 4.5 µm and times around 200 ps, and the relaxation rate was found to be governed equally by Elliott‑Yafet and D’yakonov‑Perel mechanisms.

Abstract

We performed spin transport measurements on boron nitride based single layer graphene devices with mobilities up to 40 000 cm${}^{2}$ V${}^{\ensuremath{-}1}$ s${}^{\ensuremath{-}1}$. We could observe spin transport over lengths up to 20 $\ensuremath{\mu}$m at room temperature, the largest distance measured so far for graphene. Due to enhanced charge-carrier diffusion, spin relaxation lengths are measured up to 4.5 $\ensuremath{\mu}$m. The relaxation times are similar to values for lower quality SiO${}_{2}$-based devices, around 200 ps. We find that the relaxation rate is determined in almost equal measures by the Elliott-Yafet and D'Yakonov-Perel mechanisms.