Giant oscillating thermopower at oxide interfaces.
- Pallecchi I Department of Physics, CNR-SPIN and Genova University, via Dodecaneso 33, Genova 16146, Italy.
- Telesio F Department of Physics, CNR-SPIN and Genova University, via Dodecaneso 33, Genova 16146, Italy.
- Li D Department of Quantum Matter Physics,, University of Geneva, 24 Quai E.-Ansermet, Geneva 4 1211, Switzerland.
- Fête A Department of Quantum Matter Physics,, University of Geneva, 24 Quai E.-Ansermet, Geneva 4 1211, Switzerland.
- Gariglio S Department of Quantum Matter Physics,, University of Geneva, 24 Quai E.-Ansermet, Geneva 4 1211, Switzerland.
- Triscone JM Department of Quantum Matter Physics,, University of Geneva, 24 Quai E.-Ansermet, Geneva 4 1211, Switzerland.
- Filippetti A CNR-IOM UOS Cagliari, c/o Dipartimento di Fisica, Università di Cagliari, S.P. Monserrato-Sestu Km.0,700, Monserrato (Ca) 09042, Italy.
- Delugas P CompuNet, Istituto Italiano di Tecnologia-IIT, Via Morego 30, Genova 16163, Italy.
- Fiorentini V Dipartimento di Fisica, Università di Cagliari, CNR-IOM, S.P. Monserrato-Sestu Km.0,700, Monserrato (Ca) 09042, Italy.
- Marré D Department of Physics, CNR-SPIN and Genova University, via Dodecaneso 33, Genova 16146, Italy.
- 2015-03-28
Published in:
- Nature communications. - 2015
English
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.
- Language
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- English
- Open access status
- gold
- Identifiers
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- DOI 10.1038/ncomms7678
- PMID 25813265
- Persistent URL
- https://sonar.ch/global/documents/220472
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