Graphene on SrTiO3

TL;DR

This study analyzes how different impurity scattering mechanisms affect graphene's electrical transport on SrTiO3 substrates, revealing the dominance of charged impurities near neutrality and the coexistence of multiple scattering processes at higher densities.

Contribution

It provides a dual-model framework for understanding impurity scattering effects on graphene transport across varying carrier densities on SrTiO3.

Findings

Charged impurity scattering dominates near charge neutrality.

A dual model including resonant defects explains high-density behavior.

Different scattering mechanisms can dominate at different densities.

Abstract

We study carrier transport through graphene on SrTiO$_3$ substrates by considering relative contributions of Coulomb and resonant impurity scattering to graphene resistivity. We establish that charged impurity scattering must dominate graphene transport as the charge neutrality point is approached by lowering the carrier density, and in the higher density regime away from the neutrality point a dual model including both charged impurities and resonant defects gives an excellent description of graphene transport on SrTiO$_3$ substrates. We further establish that the non-universal high-density behavior of $\sigma(n)$ in different graphene samples on various substrates arises from the competition among different scattering mechanisms, and it is in principle entirely possible for graphene transport to be dominated by qualitatively different scattering mechanisms at high and low carrier densities.