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
N. 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 Michigan-Ann Arbor, University of California
Evgeny Y. Tsymbal, University of Nebraska at LincolnFollow
M. S. Rzchowski, University of Nebraska - Lincoln
C. B. Eom, University of Wisconsin

Date of this Version

3-29-2022

Citation

APL Mater. 10, 031115 (2022); https://doi.org/10.1063/5.0067445

Comments

Open Access.

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.