Carrier-Density Control of the SrTiO3 (001) Surface 2D Electron Gas studied by ARPES

Siobhan McKeown Walker; Flavio Yair Bruno; Zhiming Wang; Alberto de la Torre; Sara Riccó; Anna Tamai; Timur K Kim; Moritz Hoesch; Ming Shi; Mohammad Saeed Bahramy; Phil D C King; Felix Baumberger

doi:10.1002/adma.201501556

Carrier-Density Control of the SrTiO3 (001) Surface 2D Electron Gas studied by ARPES

Adv Mater. 2015 Jul 8;27(26):3894-9. doi: 10.1002/adma.201501556. Epub 2015 May 22.

Authors

Affiliations

¹ Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211, Geneva, Switzerland.
² Swiss Light Source, Paul Scherrer Institute, 5232, Villigen, Switzerland.
³ Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, UK.
⁴ Quantum-Phase Electronics Center, Department of Applied Physics, University of Tokyo, 113-8656, Tokyo, Japan.
⁵ RIKEN Center for Emergent Matter Science, 351-0198, Wako, Japan.
⁶ SUPA School of Physics and Astronomy, University of St Andrews, KY16 9SS, St Andrews, UK.

PMID: 26010071
DOI: 10.1002/adma.201501556

Abstract

The origin of the 2D electron gas (2DEG)stabilized at the bare surface of SrTiO3 (001) is investigated. Using high-resolution angle-resolved photoemission and core-level spectroscopy, it is shown conclusively that this 2DEG arises from light-induced oxygen vacancies. The dominant mechanism driving vacancy formation is identified, allowing unprecedented control over the 2DEG carrier density.

Keywords: 2D electron gas; angle-resolved photoemission spectroscopy; oxygen vacancies; strontium titanate.