Asymmetric Electron-Hole Decoherence in Ion-Gated Epitaxial Graphene

TL;DR

This study reveals asymmetric electron-hole decoherence in ionic liquid-gated epitaxial graphene, showing distinct gate-dependent decoherence rates for holes and electrons, with implications for understanding microscopic scattering mechanisms.

Contribution

It provides the first detailed analysis of asymmetric electron-hole decoherence in epitaxial graphene under ionic gating, highlighting different decoherence behaviors for electrons and holes.

Findings

Hole decoherence rate increases with negative gate voltage.

Electron decoherence rate remains relatively constant across gate voltages.

Hole decoherence can be as large as electron decoherence by a factor of two.

Abstract

We report on asymmetric electron-hole decoherence in epitaxial graphene gated by an ionic liquid. The observed negative magnetoresistance near zero magnetic field for different gate voltages, analyzed in the framework of weak localization, gives rise to distinct electron-hole decoherence. The hole decoherence rate increases prominently with decreasing negative gate voltage while the electron decoherence rate does not exhibit any substantial gate dependence. Quantitatively, the hole decoherence rate is as large as the electron decoherence rate by a factor of two. We discuss possible microscopic origins including spin-exchange scattering consistent with our experimental observations.