Tunability of conduction at the LaAlO3/SrTiO3 heterointerface: Thickness and compositional studies

E. Breckenfeld, N. Bronn, N. Mason, L. W. Martin

Research output: Contribution to journalArticle

Abstract

The role of chemistry, film thickness, and oxygen pressure in influencing the electrical and thermal transport properties of LaAlO3/SrTiO3 heterointerfaces is explored. Unit-cell precise growth was accomplished for films between 3 and 160 unit cells thick using reflection high-energy electron diffraction-assisted pulsed-laser deposition. Subsequent temperature-dependent studies of electrical resistivity reveal three important observations: (1) by tuning the laser fluence, we can systematically tune the interfacial conductance in a step-wise manner in this system, (2) all films exhibit a critical thickness of 3-4 unit cells for the onset of conduction, and (3) the nature of the conductance is highly influenced by the stoichiometry of the LaAlO3 film with La-deficient samples showing dramatic changes with thickness, while stoichiometric and La-excess films show little dependence. Time-domain thermoreflectance studies show a diminished interfacial thermal conductance for the La-deficient films when compared to La-excess and stoichiometric films, suggesting that the interfacial conductance is more influenced by extrinsic factors such as oxygen deficiency.

Original languageEnglish (US)
Article number121610
JournalApplied Physics Letters
Volume105
Issue number12
DOIs
StatePublished - Sep 22 2014

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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