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Calendar: ALS Calendar
Title: ALS Special Seminar | Nick Plumb
When: 10/15/2012 1:00 PM - 2:00 PM
Description: ALS Special Seminar

Mon, Oct 15, 2012
1 - 2pm
6-2202

Host:
Eli Rotenberg

Presented by:
Nick Plumb
Swiss Light Source, Paul Scherrer Institut, 5232 Villigen-PSI, Switzerland

Title:
From Surface to Interface: A Systematic Study of Low-Dimensional Electron Gases on SrTiO3 and in LaAlO3/SrTiO3

Abstract:
Transition metal oxide surfaces, thin films, and interfaces are at the frontier of developing next-generation multifunctional devices. A primary example is the LaAlO3/SrTiO3 (LAO/STO) interface, where a metallic 2D electron gas (2DEG) capable of superconducting and magnetic behavior emerges – despite the fact that bulk LAO and STO are nonmagnetic insulators. Theories about the 2DEG’s origin have naturally focused on interface-specific phenomena (e.g., intermixing, congregation of oxygen vacancies, or the ‘polar catastrophe’ induced by LAO). However, recent experiments found that bare STO itself can host a universal low-dimension electron gas. This raises the possibility that the two systems are connected, and each may be able to teach us about the origins of metallicity in the other. With this in mind, we have performed a systematic study of the electronic structure of various bare STO substrates and LAO/STO interfaces. In situ high-resolution angle-resolved photoemission spectroscopy (ARPES) and soft x-ray ARPES (SX-ARPES), as well as resonant inelastic x-ray scattering (RIXS) uncover remarkable similarities between the electron gases in these systems. Our results suggest that STO and LAO/STO are intimately connected, and we propose that polar structural distortions in STO play a key role in 2DEG formation.
Location: 6-2202 Conf Room
Author: Adriana Reza