Polaronic metal state at the LaAlO₃/SrTiO₃ interface

Cancellieri, C.; Mishchenko, A. S.; Aschauer, Ulrich Johannes; Filippetti, A.; Faber, C.; Barišić, O. S.; Rogalev, V. A.; Schmitt, T.; Nagaosa, N.; Strocov, V. N. (2016). Polaronic metal state at the LaAlO₃/SrTiO₃ interface. Nature communications, 7(1), p. 10386. Nature Publishing Group 10.1038/ncomms10386

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Interplay of spin, charge, orbital and lattice degrees of freedom in oxide heterostructures results in a plethora of fascinating properties, which can be exploited in new generations of electronic devices with enhanced functionalities. The paradigm example is the interface between the two band insulators LaAlO3 and SrTiO3 that hosts a two-dimensional electron system. Apart from the mobile charge carriers, this system exhibits a range of intriguing properties such as field effect, superconductivity and ferromagnetism, whose fundamental origins are still debated. Here we use soft-X-ray angle-resolved photoelectron spectroscopy to penetrate through the LaAlO3 overlayer and access charge carriers at the buried interface. The experimental spectral function directly identifies the interface charge carriers as large polarons, emerging from coupling of charge and lattice degrees of freedom, and involving two phonons of different energy and thermal activity. This phenomenon fundamentally limits the carrier mobility and explains its puzzling drop at high temperatures.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Departement of Chemistry and Biochemistry

UniBE Contributor:

Aschauer, Ulrich Johannes

Subjects:

500 Science > 530 Physics
500 Science > 540 Chemistry

ISSN:

2041-1723

Publisher:

Nature Publishing Group

Language:

English

Submitter:

Ulrich Johannes Aschauer

Date Deposited:

04 Feb 2016 08:34

Last Modified:

18 Nov 2018 02:00

Publisher DOI:

10.1038/ncomms10386

BORIS DOI:

10.7892/boris.75985

URI:

https://boris.unibe.ch/id/eprint/75985

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