Theory of Interfacial Plasmon-Phonon Scattering in Supported Graphene

TL;DR

This paper develops a theoretical framework for understanding how interfacial plasmon-phonon modes affect electron mobility in supported graphene, revealing substrate-dependent behaviors and temperature effects.

Contribution

It introduces a new theory describing coupling between graphene plasmons and substrate surface phonons, predicting interfacial modes and their impact on mobility.

Findings

H-BN yields highest peak mobility.

HfO2 supports high mobility at high carrier densities.

Temperature dependence of mobility diminishes at high carrier concentrations.

Abstract

One of the factors limiting electron mobility in supported graphene is remote phonon scattering. We formulate the theory of the coupling between graphene plasmon and substrate surface polar phonon (SPP) modes, and find that it leads to the formation of interfacial plasmon-phonon (IPP) modes, from which the phenomena of dynamic anti-screening and screening of remote phonons emerge. The remote phonon-limited mobilities for SiO$_{2}$, HfO$_{2}$, h-BN and Al$_{2}$O$_{3}$ substrates are computed using our theory. We find that h-BN yields the highest peak mobility, but in the practically useful high-density range the mobility in HfO$_{2}$-supported graphene is high, despite the fact that HfO$_{2}$ is a high-$\kappa$ dielectric with low-frequency modes. Our theory predicts that the strong temperature dependence of the total mobility effectively vanishes at very high carrier concentrations. The effects of polycrystallinity on IPP scattering are also discussed.