Unconventional transport through graphene on SrTiO 3: A plausible effect of SrTiO3 phase-transitions

Surajit Saha, Orhan Kahya, Manu Jaiswal, Amar Srivastava, Anil Annadi, Jayakumar Balakrishnan, Alexandre Pachoud, Chee Tat Toh, Byung Hee Hong, Jong Hyun Ahn, T. Venkatesan, Barbaros Özyilmaz

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Abstract

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 T550 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.

Original languageEnglish
Article number6173
JournalScientific reports
Volume4
DOIs
Publication statusPublished - 2014 Aug 22

All Science Journal Classification (ASJC) codes

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    Saha, S., Kahya, O., Jaiswal, M., Srivastava, A., Annadi, A., Balakrishnan, J., Pachoud, A., Toh, C. T., Hong, B. H., Ahn, J. H., Venkatesan, T., & Özyilmaz, B. (2014). Unconventional transport through graphene on SrTiO 3: A plausible effect of SrTiO3 phase-transitions. Scientific reports, 4, [6173]. https://doi.org/10.1038/srep06173