Electronic Reconstruction at the Polar (111)-oriented Oxide Interface

Authors

S. Ryu, University of Wisconsin - Madison
H. Zhou, Argonne National Laboratory
Tula R. Paudel, University of Nebraska-LincolnFollow
Neil Campbell, University of Wisconsin - Madison
J. Podkaminer, University of Wisconsin - Madison
C. W. Bark, University of Wisconsin - Madison
T. Hernandez, University of Wisconsin - Madison
D. D. Fong, Argonne National Laboratory
Y. Zhang, University of Michigan-Ann Arbor
L. Xie, University of Michigan-Ann Arbor
X. Q. Pan, University of California, Irvine
Evgeny Y. Tsymbal, University of Nebraska-LincolnFollow
M. S. Rzchowski, University of Nebraska-Lincoln
Chang-Beom Eom, University of Wisconsin-MadisonFollow

ORCID IDs

Ryu https://orcid.org/0000-0002-9617-4958

Paudel https://orcid.org/0000-0002-9952-9435

Bark https://orcid.org/0000-0002-9394-4240

Fong https://orcid.org/0000-0001-5930-8243

Eom https://orcid.org/0000-0002-8854-1439

Document Type

Article

Date of this Version

2022

Citation

APL Materials (March 2022) 10(3): 031115

doi: 10.1063/5.0067445

Supplementary materials are available at https://www.scitation.org/doi/suppl/10.1063/5.0067445

Comments

Copyright 2022, the authors. Open access

License: CC BY 4.0

Abstract

Atomically flat (111) interfaces between insulating perovskite oxides provide a landscape for new electronic phenomena. For example, the graphene-like coordination between interfacial metallic ion layer pairs can lead to topologically protected states [Xiao et al., Nat. Commun. 2, 596 (2011) and A. Rüegg and G. A. Fiete, Phys. Rev. B 84, 201103 (2011)]. The metallic ion/metal oxide bilayers that comprise the unit cell of the perovskite (111) heterostructures require the interface to be polar, generating an intrinsic polar discontinuity [Chakhalian et al., Nat. Mater. 11, 92 (2012)]. Here, we investigate epitaxial heterostructures of (111)-oriented LaAlO₃/SrTiO₃ (LAO/STO). We find that during heterostructure growth, the LAO overlayer eliminates the structural reconstruction of the STO (111) surface with an electronic reconstruction, which determines the properties of the resulting two-dimensional conducting gas. This is confirmed by transport measurements, direct determination of the structure and atomic charge from coherent Bragg rod analysis, and theoretical calculations of electronic and structural characteristics. Interfacial behaviors of the kind discussed here may lead to new growth control parameters useful for electronic devices.