title: Giant oscillating thermopower at oxide interfaces.
abstract: Understanding the nature of charge carriers at the LaAlO3/SrTiO3 interface is one of the major open issues in the full comprehension of the charge confinement phenomenon in oxide heterostructures. Here, we investigate thermopower to study the electronic structure in LaAlO3/SrTiO3 at low temperature as a function of gate field. In particular, under large negative gate voltage, corresponding to the strongly depleted charge density regime, thermopower displays high negative values of the order of 10(4)-10(5) μVK(-1), oscillating at regular intervals as a function of the gate voltage. The huge thermopower magnitude can be attributed to the phonon-drag contribution, while the oscillations map the progressive depletion and the Fermi level descent across a dense array of localized states lying at the bottom of the Ti 3d conduction band. This study provides direct evidence of a localized Anderson tail in the two-dimensional electron liquid at the LaAlO3/SrTiO3 interface.
authors: Department of Physics, CNR-SPIN and Genova University, via Dodecaneso 33, Genova 16146, Italy.
authors: Ilaria
authors: I
authors: Pallecchi
authors: Department of Physics, CNR-SPIN and Genova University, via Dodecaneso 33, Genova 16146, Italy.
authors: Francesca
authors: F
authors: Telesio
authors: Department of Quantum Matter Physics,, University of Geneva, 24 Quai E.-Ansermet, Geneva 4 1211, Switzerland.
authors: Danfeng
authors: D
authors: Li
authors: Department of Quantum Matter Physics,, University of Geneva, 24 Quai E.-Ansermet, Geneva 4 1211, Switzerland.
authors: Alexandre
authors: A
authors: Fête
authors: Department of Quantum Matter Physics,, University of Geneva, 24 Quai E.-Ansermet, Geneva 4 1211, Switzerland.
authors: Stefano
authors: S
authors: Gariglio
authors: Department of Quantum Matter Physics,, University of Geneva, 24 Quai E.-Ansermet, Geneva 4 1211, Switzerland.
authors: Jean-Marc
authors: JM
authors: Triscone
authors: CNR-IOM UOS Cagliari, c/o Dipartimento di Fisica, Università di Cagliari, S.P. Monserrato-Sestu Km.0,700, Monserrato (Ca) 09042, Italy.
authors: Alessio
authors: A
authors: Filippetti
authors: CompuNet, Istituto Italiano di Tecnologia-IIT, Via Morego 30, Genova 16163, Italy.
authors: Pietro
authors: 0000000308927655
authors: P
authors: Delugas
authors: Dipartimento di Fisica, Università di Cagliari, CNR-IOM, S.P. Monserrato-Sestu Km.0,700, Monserrato (Ca) 09042, Italy.
authors: Vincenzo
authors: 0000000337948092
authors: V
authors: Fiorentini
authors: Department of Physics, CNR-SPIN and Genova University, via Dodecaneso 33, Genova 16146, Italy.
authors: Daniele
authors: D
authors: Marré