Probing electronic dead layers in homoepitaxial n -SrTiO3(001) films

S. A. Chambers, Dooyong Lee, Z. Yang, Yi Huang, W. Samarakoon, H. Zhou, P. V. Sushko, Tristan K Truttmann, L. W. Wangoh, T. L. Lee, J. Gabel, B. Jalan

Research output: Contribution to journalArticlepeer-review

Abstract

We combine state-of-the-art oxide epitaxial growth by hybrid molecular beam epitaxy with transport, x-ray photoemission, and surface diffraction, along with classical and first-principles quantum mechanical modeling to investigate the nuances of insulating layer formation in otherwise high-mobility homoepitaxial n-SrTiO3(001) films. Our analysis points to charge immobilization at the buried n-SrTiO3/undoped SrTiO3(001) interface as well as within the surface contamination layer resulting from air exposure as the drivers of electronic dead-layer formation. As Fermi level equilibration occurs at the surface and the buried interface, charge trapping reduces the sheet carrier density (n2D) and renders the n-STO film insulating if n2D falls below the critical value for the metal-to-insulator transition.

Original languageEnglish (US)
Article number070903
JournalAPL Materials
Volume10
Issue number7
DOIs
StatePublished - Jul 1 2022

Bibliographical note

Funding Information:
Work at PNNL was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences (Award No. 10122). WSS acknowledges support from the OSU-PNNL Graduate Fellowship. Work at UMN was supported by the U.S. Department of Energy (Grant No. DE-SC002021). Structural characterizations were carried out at the University of Minnesota Characterization Facility, which receives partial support from NSF through the MRSEC program (Award No. DMR-2011401). ZY acknowledges support from the Air Force Office of Scientific Research (AFOSR) (Grant No. FA9550-21-1-0025). YH was supported by the Fine Theoretical Physics Institute of UMN. Modeling was done using the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy (Contract No. DE-AC02-05CH11231) using NERSC (Award No. BES-ERCAP0021800). This research used resources at the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science user facility operated for the DOE Office of Science by Argonne National Laboratory (Contract No. DE-AC02-06CH11357).

Publisher Copyright:
© 2022 Author(s).

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