• 文献标题:   Unraveling the Impact of Graphene Addition to Thermoelectric SrTiO3 and La-Doped SrTiO3 Materials: A Density Functional Theory Study
  • 文献类型:   Article
  • 作  者:   TSE J, AZIZ A, FLITCROFT JM, SKELTON JM, GILLIE LJ, PARKER SC, COOKE DJ, MOLINARI M
  • 作者关键词:   thermoelectric, graphene/strontium titanate composite material, electronic structure, structural dynamic, thermal transport, graphene adsorption on perovskite oxide
  • 出版物名称:   ACS APPLIED MATERIALS INTERFACES
  • ISSN:   1944-8244 EI 1944-8252
  • 通讯作者地址:  
  • 被引频次:   8
  • DOI:   10.1021/acsami.1c10865 EA AUG 2021
  • 出版年:   2021

▎ 摘  要

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/m(2) 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.