Infrared study of the quasi-two-dimensional electron system at the interface between SrTiO3 and crystalline or amorphous LaAlO3
Journal article, 2018

We have used grazing-angle infrared spectroscopy to detect the Berreman effect (BE) in the quasi-two-dimensional electron system (q-2DES) which forms spontaneously at the interface between SrTiO 3 (STO) and a thin film of LaAlO 3 (LAO). From the BE, which allows one to study longitudinal optical excitations in ultrathin films like the q-2DES, we have extracted at different temperatures its thickness, the charge density and mobility of the carriers under crystalline LAO (sample A), and the charge density under amorphous LAO (sample B). The latter quantity turns out to be higher than in sample A, but a comparison with Hall measurements shows that under amorphous LAO the charges are partly localized at low T with a low activation energy (about 190 K in units of kB) and are thermally activated according to a model for large polarons. The thickness of the q-2DES extracted from our spectra turns out to be 4±1 nm for crystalline LAO and 7±2 nm for amorphous LAO.


A. Nucara

Sapienza University of Rome

M. Corasaniti

Sapienza University of Rome

Alexei Kalaboukhov

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

M. Ortolani

Sapienza University of Rome

E. Falsetti

Sapienza University of Rome

A. Sambri

CNR - SuPerconducting and other INnovative materials and devices institute, Napoli

F. Miletto Granozio

CNR - SuPerconducting and other INnovative materials and devices institute, Napoli

F. Capitani

SOLEIL Synchrotron

J. B. Brubach

SOLEIL Synchrotron

P. Roy

SOLEIL Synchrotron

U. Schade


P. Calvani

Sapienza University of Rome

Physical Review B

2469-9950 (ISSN) 2469-9969 (eISSN)

Vol. 97 15 155126

Subject Categories

Atom and Molecular Physics and Optics

Other Physics Topics

Condensed Matter Physics



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