Electron Transport at the TiO₂ Surfaces of Rutile, Anatase, and Strontium Titanate: The Influence of Orbital Corrugation

Tarapada Sarkar; Kalon Gopinadhan; Jun Zhou; Surajit Saha; J M D Coey; Yuan Ping Feng; Ariando; T Venkatesan

doi:10.1021/acsami.5b06694

Electron Transport at the TiO₂ Surfaces of Rutile, Anatase, and Strontium Titanate: The Influence of Orbital Corrugation

ACS Appl Mater Interfaces. 2015 Nov 11;7(44):24616-21. doi: 10.1021/acsami.5b06694. Epub 2015 Oct 28.

Authors

Tarapada Sarkar^{1

2}, Kalon Gopinadhan², Jun Zhou¹, Surajit Saha², J M D Coey³, Yuan Ping Feng¹, Ariando^{1

2}, T Venkatesan^{1

2

4

5}

Affiliations

¹ Department of Physics, National University of Singapore , Singapore 117542.
² NUSNNI-NanoCore, National University of Singapore , Singapore 117576.
³ School of Physics and CRANN, Trinity College , Dublin 2, Ireland.
⁴ Department of Electrical and Computer Engineering, National University of Singapore , Singapore 117576.
⁵ Department of Materials Science and Engineering, National University of Singapore , Singapore 119077.

PMID: 26509804
DOI: 10.1021/acsami.5b06694

Abstract

The two-dimensional electron gas in SrTiO3 created by an overlayer of amorphous LaAlO3 is compared with those at the TiO2-terminated surfaces of rutile and anatase. Differences in conductivity are explained in terms of the limiting Ti-O-Ti bond angles (orbital corrugation), band dispersion, and polaron formation. At 300 K, the sheet conductivity and mobility of anatase exceed those for SrTiO3 or rutile by one or two orders of magnitude, respectively. The electrons in rutile become localized below 25 K.

Keywords: anatase; anisotropic conductivity; bond angles; mobility; rutile; strontium titanate; two-dimensional electron gas.

Publication types

Research Support, Non-U.S. Gov't