Quantum Conductance Probing of Oxygen Vacancies in SrTiO3 Epitaxial Thin Film using Graphene

Kyeong Tae Kang; Haeyong Kang; Jeongmin Park; Dongseok Suh; Woo Seok Choi

doi:10.1002/adma.201700071

Quantum Conductance Probing of Oxygen Vacancies in SrTiO₃ Epitaxial Thin Film using Graphene

Adv Mater. 2017 May;29(18). doi: 10.1002/adma.201700071. Epub 2017 Mar 16.

Authors

Kyeong Tae Kang^{1

2}, Haeyong Kang³, Jeongmin Park^{2

3}, Dongseok Suh³, Woo Seok Choi¹

Affiliations

¹ Department of Physics, Sungkyunkwan University, Suwon, 16419, Korea.
² Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Suwon, 16419, Korea.
³ Department of Energy Sciences, Sungkyunkwan University, Suwon, 16419, Korea.

PMID: 28301058
DOI: 10.1002/adma.201700071

Abstract

Quantum Hall conductance in monolayer graphene on an epitaxial SrTiO₃ (STO) thin film is studied to understand the role of oxygen vacancies in determining the dielectric properties of STO. As the gate-voltage sweep range is gradually increased in the device, systematic generation and annihilation of oxygen vacancies, evidenced from the hysteretic conductance behavior in the graphene, are observed. Furthermore, based on the experimentally observed linear scaling relation between the effective capacitance and the voltage sweep range, a simple model is constructed to manifest the relationship among the dielectric properties of STO with oxygen vacancies. The inherent quantum Hall conductance in graphene can be considered as a sensitive, robust, and noninvasive probe for understanding the electronic and ionic phenomena in complex transition-metal oxides without impairing the oxide layer underneath.

Keywords: SrTiO3; epitaxial thin films; graphene; oxygen vacancies; quantum Hall conductance.