Flexural phonon scattering induced by electrostatic gating in graphene

TL;DR

This study investigates how electrostatic gating breaks graphene's mirror symmetry, enabling flexural phonon scattering that limits carrier mobility, with implications for device design and understanding phonon interactions.

Contribution

It reveals the impact of gate-induced symmetry breaking on flexural phonon scattering and mobility in graphene through first-principles calculations.

Findings

Gate-induced flexural phonon scattering can limit mobility.

Carrier density and temperature affect mobility scaling.

Device symmetry influences phonon scattering and mobility.

Abstract

Graphene has an extremely high carrier mobility partly due to its planar mirror symmetry inhibiting scattering by the highly occupied acoustic flexural phonons. Electrostatic gating of a graphene device can break the planar mirror symmetry yielding a coupling mechanism to the flexural phonons. We examine the effect of the gate-induced one-phonon scattering on the mobility for several gate geometries and dielectric environments using first-principles calculations based on density functional theory (DFT) and the Boltzmann equation. We demonstrate that this scattering mechanism can be a mobility-limiting factor, and show how the carrier density and temperature scaling of the mobility depends on the electrostatic environment. Our findings may explain the high deformation potential for in-plane acoustic phonons extracted from experiments and furthermore suggest a direct relation between device symmetry and resulting mobility.