Temperature-Dependent Electron-Electron Interaction in Graphene on SrTiO3

TL;DR

This study investigates how temperature affects electron-electron interactions in graphene on SrTiO3, revealing strong deviations from linear dispersion at low temperatures, indicating enhanced correlations.

Contribution

It demonstrates temperature-dependent modifications in graphene's electronic structure on SrTiO3, highlighting potential for strongly correlated phases and substrate engineering.

Findings

Spectral width and Fermi velocity similar to graphene on BN

Strong deviation from linear dispersion near charge neutrality at low temperatures

Potential for realizing strongly correlated electron phases

Abstract

The electron band structure of graphene on SrTiO3 substrate has been investigated as a function of temperature. The high-resolution angle-resolved photoemission study reveals that the spectral width at Fermi energy and the Fermi velocity of graphene on SrTiO3 are comparable to those of graphene on a BN substrate. Near the charge neutrality, the energy-momentum dispersion of graphene exhibits a strong deviation from the well-known linearity, which is magnified as temperature decreases. Such modification resembles the characteristics of enhanced electron-electron interaction. Our results not only suggest that SrTiO3 can be a plausible candidate as a substrate material for applications in graphene-based electronics, but also provide a possible route towards the realization of a new type of strongly correlated electron phases in the prototypical two-dimensional system via the manipulation of temperature and a proper choice of dielectric substrates.