Metallic and Insulating Oxide Interfaces Controlled by Electronic Correlations

Authors

H. W. Jang, University of Wisconsin - Madison
D. A. Felker, University of Wisconsin - Madison
C. W. Bark, University of Wisconsin - Madison
Y. Wang, University of Nebraska-Lincoln
Manish K. Niranjan, University of Nebraska-LincolnFollow
C. T. Nelson, University of Michigan - Ann Arbor
Y. Zhang, University of Michigan - Ann Arbor
D. Su, Center for Functional Nanomaterials
C. M. Folkman, University of Wisconsin - Madison
S. H. Baek, University of Wisconsin - Madison
S. Lee, University of Wisconsin - Madison
K. Janicka, University of Nebraska - Lincoln
Y. Zhu, Center for Functional Nanomaterials
X. Q. Pan, University of Michigan - Ann ArborFollow
D. D. Fong, Argonne National Laboratory
Evgeny Y. Tsymbal, University of Nebraska-LincolnFollow
M. S. Rzchowski, University of Wisconsin - Madison
Chang-Beom Eom, University of Wisconsin-MadisonFollow

Date of this Version

2011

Comments

Published in SCIENCE, vol 331, issue 6019 (February 18, 2011): 886-889.

Abstract

The formation of two-dimensional electron gases (2DEGs) at complex oxide interfaces is directly influenced by the oxide electronic properties. We investigated how local electron correlations control the 2DEG by inserting a single atomic layer of a rare-earth oxide (RO) [(R is lanthanum (La), praseodymium (Pr), neodymium (Nd), samarium (Sm), or yttrium (Y)] into an epitaxial strontium titanate oxide (SrTiO₃) matrix using pulsed-laser deposition with atomic layer control. We find that structures with La, Pr, and Nd ions result in conducting 2DEGs at the inserted layer, whereas the structures with Sm or Y ions are insulating. Our local spectroscopic and theoretical results indicate that the interfacial conductivity is dependent on electronic correlations that decay spatially into the SrTiO₃ matrix. Such correlation effects can lead to new functionalities in designed heterostructures.