• 文献标题:   Unconventional Transport through Graphene on SrTiO3: A Plausible Effect of SrTiO3 Phase-Transitions
  • 文献类型:   Article
  • 作  者:   SAHA S, KAHYA O, JAISWAL M, SRIVASTAVA A, ANNADI A, BALAKRISHNAN J, PACHOUD A, TOH CT, HONG BH, AHN JH, VENKATESAN T, OZYILMAZ B
  • 作者关键词:  
  • 出版物名称:   SCIENTIFIC REPORTS
  • ISSN:   2045-2322
  • 通讯作者地址:   Natl Univ Singapore
  • 被引频次:   18
  • DOI:   10.1038/srep06173
  • 出版年:   2014

▎ 摘  要

High-k dielectric oxides are supposedly ideal gate-materials for ultra-high doping in graphene and other 2D-crystals. Here, we report a temperature-dependent electronic transport study on chemical vapor deposited-graphene gated with SrTiO3 (STO) thin film substrate. At carrier densities away from charge neutrality point the temperature-dependent resistivity of our graphene samples on both STO and SiO2/Si substrates show metallic behavior with contributions from Coulomb scattering and flexural phonons attributable to the presence of characteristic quasi-periodic nano-ripple arrays. Significantly, for graphene samples on STO substrates we observe an anomalous 'slope-break' in the temperature-dependent resistivity for T = 50 to 100 K accompanied by a decrease in mobility above 30 K. Furthermore, we observe an unusual decrease in the gate-induced doping-rate at low temperatures, despite an increase in dielectric constant of the substrate. We believe that a complex mechanism is at play as a consequence of the structural phase transition of the underlying substrate showing an anomalous transport behavior in graphene on STO. The anomalies are discussed in the context of Coulomb as well as phonon scattering.