Transport through graphene on SrTiO3

TL;DR

This study investigates how the high dielectric constant of SrTiO3 substrates influences the electronic transport properties of graphene, revealing suppressed interactions and altered resistance behaviors, especially in quantum Hall regimes.

Contribution

It demonstrates that SrTiO3 effectively screens electron-electron interactions in graphene, significantly affecting quantum Hall phenomena and transport gaps, which was previously not well understood.

Findings

Screening of electron-electron interactions by SrTiO3

Altered behavior of longitudinal resistance in N=0 Landau level

Suppression of transport gap in graphene nano-ribbons

Abstract

We report transport measurements through graphene on SrTiO3 substrates as a function of magnetic field B, carrier density n, and temperature T. The large dielectric constant of SrTiO3 screens very effectively long-range electron-electron interactions and potential fluctuations, making Dirac electrons in graphene virtually non-interacting. The absence of interactions results in a unexpected behavior of the longitudinal resistance in the N=0 Landau level, and in a large suppression of the transport gap in nano-ribbons. The "bulk" transport properties of graphene at B=0T, on the contrary, are completely unaffected by the substrate dielectric constant.