Polar catastrophe and electronic reconstructions at the LaAlO3/SrTiO3 interface: evidence from optical second harmonic generation

SAVOIA, ANNUNZIATA and RISTIC, ZORAN and SCOTTI DI UCCIO, UMBERTO and MARRUCCI, LORENZO (2009) Polar catastrophe and electronic reconstructions at the LaAlO3/SrTiO3 interface: evidence from optical second harmonic generation. [Pubblicazione su rivista scientifica]

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Abstract

The so-called “polar catastrophe,” a sudden electronic reconstruction taking place to compensate for the interfacial ionic polar discontinuity, is currently considered as a likely factor to explain the surprising conductivity of the interface between the insulators LaAlO3 and SrTiO3. We applied optical second harmonic generation, a technique that a priori can detect both mobile and localized interfacial electrons, to investigating the electronic polar reconstructions taking place at the interface. As the LaAlO3 film thickness is increased, we identify two abrupt electronic rearrangements: the first takes place at a thickness of unit cells, in the insulating state; the second occurs at a thickness of 4–6 unit cells, i.e., just above the threshold for which the samples become conducting. Two possible physical scenarios behind these observations are proposed. The first is based on an electronic transfer into localized electronic states at the interface that acts as a precursor of the conductivity onset. In the second scenario, the signal variations are attributed to the strong ionic relaxations taking place in the LaAlO3 layer.

Tipologia di documento:Pubblicazione su rivista scientifica
Parole chiave:Oxides, second harmonic generation, interface
Settori scientifico-disciplinari MIUR:Non specificato
Stato del full text:Accessibilità ristretta
Data:2009
Altri Autori:A. Savoia, D. Paparo, P. Perna, Z. Ristic, M. Salluzzo, F. Miletto Granozio, U. Scotti di Uccio, C. Richter, S. Thiel, J. Mannhart, L. Marrucci
Numero di pagine:6
Intervallo di pagina:075110-1-075110-6
Volume:80
Dipartimento o Struttura:Dipartimento di Scienze Fisiche
Numero identificativo:10.1103/PhysRevB.80.075110
Titolo rivista/pubblicazione:PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS
Numero di sistema:7589
Depositato il:21 Ottobre 2010 08:57
Ultima modifica:21 Ottobre 2010 08:57

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