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Calendar: ALS Calendar
Title: ALS Special Seminar | Slavo Nemsak
When: 10/ 1/2013 9:00 AM - 10:00 AM
Description: ALS Special Seminar

Tuesday, October 1, 2013
​6-2202 ​Conf Rm
9:00 - 10:00am

Host:
​Zahid Hussain

Presented by:
Slavo Nemšák
UC Davis

Title:
Direct observation of a 2-dimensional electron gas at the buried interface between GdTiO3 and SrTiO3 via standing-wave and resonant photoemission

Abstract:
Recently, interfaces between various complex oxides have been broadly studied due to their unique properties such as strong electron correlations, superconductivity, and magnetism. The presence of a 2D electron gas (2DEG) formed at the interface between the Mott insulator GdTiO3 and the band insulator SrTiO3 was indicated by transport measurements with extremely high sheet carrier densities of 3×1014 cm-2 [1]. In this study the 2DEG was directly observed by means of angle-resolved photoemission spectroscopy (ARPES), using advanced techniques of resonant photoemission spectroscopy (ResPES) and standing-wave photoelectron spectroscopy (SW-XPS) [2]. The standing wave technique was used to extract depth-resolved information for different electronic states including 2DEG related states. Moreover, previous work shows a strong dependence of sheet resistance on the SrTiO3 quantum well thickness [3], which exhibits a hard lower limit for the creation of the 2DEG. Our most recent ARPES measurements confirm these assumptions [4]. All experimental results are further discussed and compared to density functional theory calculations [2,4].

[1] P. Moetakef et al., Appl. Phys. Lett. 99 (2011) 232116
[2] S. Nemšák et al., in preparation
[3] P. Moetakef et al., Phys. Rev. B 86 ( 2012) 201102
[4] S. Nemšák et al., in preparation

--
Adriana Reza
Administrator
Scientific Support Group
Advanced Light Source Division
Lawrence Berkeley National Lab
One Cyclotron Road
MS 6R2100
Berkeley, CA 94720

Web: http://
Email: areza@lbl.gov
Tel: 510.495.2425
Fax: 510.495.2067
Location: 6-2202
Author: areza@lbl.gov