Unraveling the Impact of Graphene Addition to Thermoelectric SrTiO3and La-Doped SrTiO3Materials: A Density Functional Theory Study

Joshua Tse, Alex Aziz, Joseph M. Flitcroft, Jonathan M. Skelton, Lisa J. Gillie, Stephen C. Parker, David J. Cooke, Marco Molinari

Research output: Contribution to journalArticlepeer-review

12 Citations (SciVal)

Abstract

We present a detailed theoretical investigation of the interaction of graphene with the SrO-terminated (001) surface of pristine and La-doped SrTiO3. The adsorption of graphene is thermodynamically favorable with interfacial adsorption energies of -0.08 and -0.32 J/m2 to pristine SrTiO3 and La-doped SrTiO3 surfaces, respectively. We find that graphene introduces C 2p states at the Fermi level, rendering the composite semimetallic, and thus the electrical properties are predicted to be highly sensitive to the amount and quality of the graphene. An investigation of the lattice dynamics predicts that graphene adsorption may lead to a 60-90% reduction in the thermal conductivity due to a reduction in the phonon group velocities, accounting for the reduced thermal conductivity of the composite materials observed experimentally. This effect is enhanced by La doping. We also find evidence that both La dopant ions and adsorbed graphene introduce low-frequency modes that may scatter heat-carrying acoustic phonons, and that, if present, these effects likely arise from stronger phonon-phonon interactions.

Original languageEnglish
Pages (from-to)41303-41314
Number of pages12
JournalACS Applied Materials and Interfaces
Volume13
Issue number34
Early online date18 Aug 2021
DOIs
Publication statusPublished - 1 Sept 2021

Bibliographical note

Funding Information:
J.M.S. is grateful to UK Research and Innovation (UKRI) for the award of a Future Leaders Fellowship (MR/T043121/1), and to the University of Manchester for the previous support of a UoM Presidential Fellowship. S.C.P. thanks the EPSRC for funding (EP/P007821/1). Calculations were performed on the Balena HPC facility at the University of Bath, the Orion computing facility at the University of Huddersfield, the ARCHER UK National Supercomputing Service via our membership of the UK HEC Materials Chemistry Consortium (MCC; EPSRC EP/L000202, EP/R029431, EP/T022213), and the THOMAS facility at the UK Materials and Molecular Modelling Hub (MMM hub; EPSRC EP/P020194/1). The authors would also like to acknowledge computing time granted through the Spanish Supercomputing Network, RES, on the Tirant 3 supercomputer located at the University of Valencia (QS-2019-3-0025 and QS-2020-1-0021). Finally, this work also used the Isambard UK National Tier-2 HPC Service ( http://gw4.ac.uk/isambard/ ) via the Resource Allocation Panel (RAP) Open Access to Tier-2 call, operated by the GW4 and the UK Met Office and funded by the EPSRC (EP/P020224/1).

Keywords

  • electronic structure
  • graphene adsorption on perovskite oxides
  • graphene/strontium titanate composite materials
  • structural dynamics
  • thermal transport
  • thermoelectrics

ASJC Scopus subject areas

  • Materials Science(all)

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