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08:45
Fabrication of Spatially Confined Complex Oxides
Published on: July 1, 2013
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Direct k-space mapping of the electronic structure in an oxide-oxide interface.
G Berner1, M Sing1, H Fujiwara2
1Physikalisches Institut and Röntgen Center for Complex Materials Systems (RCCM), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
Physical Review Letters
|August 29, 2014
Summary
The LaAlO3/SrTiO3 interface shows a two-dimensional electron system with both mobile and localized electrons. This charge dichotomy, potentially linked to oxygen vacancies, explains the interface
Area of Science:
- Condensed Matter Physics
- Materials Science
- Surface Science
Background:
- The LaAlO3/SrTiO3 interface hosts a 2D electron system (2DES) despite both being band insulators.
- Interface ferromagnetism and superconductivity have been observed, linked to local moments and confined Ti 3d electrons.
Purpose of the Study:
- To directly map the interface electronic states in k-space.
- To investigate the nature of charge carriers within the 2DES at the LaAlO3/SrTiO3 interface.
Main Methods:
- Soft X-ray Angle-Resolved Resonant Photoelectron Spectroscopy (SX-ARPES).
- Experimental mapping of interface states in momentum (k) space.
Main Results:
- Demonstration of a charge dichotomy within the 2DES.
- Identification of a mobile electron fraction contributing to Fermi surface sheets.
- Observation of a localized electron fraction at higher binding energies, possibly due to oxygen vacancies in SrTiO3.
Conclusions:
- The observed charge dichotomy provides insight into the electronic reconstruction at the LaAlO3/SrTiO3 interface.
- Oxygen vacancies in SrTiO3 are a plausible explanation for the localized charge carriers.
- Electronic reconstruction, potentially involving surface oxygen vacancies in LaAlO3, can explain the observed Fermi surface features without invoking photovoltage effects.
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