TY - JOUR
T1 - Unraveling the Impact of Graphene Addition to Thermoelectric SrTiO3 and La-Doped SrTiO3 Materials
T2 - A Density Functional Theory Study
AU - Tse, Joshua
AU - Aziz, Alex
AU - Flitcroft, Joseph
AU - Skelton, Jonathan
AU - Gillie, Lisa
AU - Parker, Stephen
AU - Cooke, David
AU - Molinari, Marco
N1 - 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).
Publisher Copyright:
© Authors 2021
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021/9/1
Y1 - 2021/9/1
N2 - 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.
AB - 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.
KW - Thermoelectrics
KW - Graphene/strontium titanate composite materials
KW - Electronic structure
KW - Structural dynamics
KW - Thermal transport
KW - Graphene adsorption on perovskite oxides
KW - graphene adsorption on perovskite oxides
KW - thermoelectrics
KW - structural dynamics
KW - thermal transport
KW - graphene/strontium titanate composite materials
KW - electronic structure
UR - https://www.scopus.com/pages/publications/85114119671
U2 - 10.1021/acsami.1c10865
DO - 10.1021/acsami.1c10865
M3 - Article
SN - 1944-8244
VL - 13
SP - 41303
EP - 41314
JO - ACS applied materials & interfaces
JF - ACS applied materials & interfaces
IS - 34
ER -
SDG 7 Affordable and Clean Energy
SDG 9 Industry, Innovation, and Infrastructure