Tunability of conduction at the LaAlO{sub 3}/SrTiO{sub 3} heterointerface: Thickness and compositional studies

Journal Article · Mon Sep 22 00:00:00 EDT 2014 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4896778· OSTI ID:22350746

Breckenfeld, E. ^[1]; Bronn, N. ^[2]; Mason, N. ^[2]; Martin, L. W. ^[3]

---

1. Department of Materials Science and Engineering and Materials Research Laboratory, University of Illinois, Urbana-Champaign, Urbana, Illinois 81801 (United States)
2. Department of Physics and Materials Research Laboratory, University of Illinois, Urbana-Champaign, Urbana, Illinois 61801 (United States)
3. Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, California 94720 (United States)

The role of chemistry, film thickness, and oxygen pressure in influencing the electrical and thermal transport properties of LaAlO{sub 3}/SrTiO{sub 3} 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 LaAlO{sub 3} 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.

• OSTI ID: 22350746
• Journal Information: Applied Physics Letters, Vol. 105, Issue 12; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALUMINATES
CRYSTAL GROWTH
ELECTRIC CONDUCTIVITY
ELECTRON DIFFRACTION
ENERGY BEAM DEPOSITION
FILMS
LANTHANUM COMPOUNDS
LASER RADIATION
PULSED IRRADIATION
REFLECTION
STOICHIOMETRY
STRONTIUM TITANATES
TEMPERATURE DEPENDENCE
THERMAL CONDUCTIVITY
THICKNESS