Detection of decoupled surface and bulk states in epitaxial orthorhombic SrIrO3 thin films
Prescott E. Evans,
Takashi Komesu,
Le Zhang,
Ding-Fu Shao,
Andrew J. Yost,
Shiv Kumar,
Eike F. Schwier,
Kenya Shimada,
Evgeny Y. Tsymbal,
Xia Hong,
P. A. Dowben
Affiliations
Prescott E. Evans
Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, Theodore Jorgensen Hall, 855 N 16th, University of Nebraska, Lincoln, Nebraska 68588-0299, USA
Takashi Komesu
Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, Theodore Jorgensen Hall, 855 N 16th, University of Nebraska, Lincoln, Nebraska 68588-0299, USA
Le Zhang
Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, Theodore Jorgensen Hall, 855 N 16th, University of Nebraska, Lincoln, Nebraska 68588-0299, USA
Ding-Fu Shao
Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, Theodore Jorgensen Hall, 855 N 16th, University of Nebraska, Lincoln, Nebraska 68588-0299, USA
Andrew J. Yost
Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, Theodore Jorgensen Hall, 855 N 16th, University of Nebraska, Lincoln, Nebraska 68588-0299, USA
Shiv Kumar
Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima 739-0046, Japan
Eike F. Schwier
Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima 739-0046, Japan
Kenya Shimada
Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima 739-0046, Japan
Evgeny Y. Tsymbal
Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, Theodore Jorgensen Hall, 855 N 16th, University of Nebraska, Lincoln, Nebraska 68588-0299, USA
Xia Hong
Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, Theodore Jorgensen Hall, 855 N 16th, University of Nebraska, Lincoln, Nebraska 68588-0299, USA
P. A. Dowben
Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, Theodore Jorgensen Hall, 855 N 16th, University of Nebraska, Lincoln, Nebraska 68588-0299, USA
We report the experimental evidence of evolving lattice distortion in high quality epitaxial orthorhombic SrIrO3(001) thin films fully strained on (001) SrTiO3 substrates. Angle-resolved X-ray photoemission spectroscopy studies show that the surface layer of 5 nm SrIrO3 films is Sr–O terminated, and subsequent layers recover the semimetallic state, with the band structure consistent with an orthorhombic SrIrO3(001) having the lattice constant of the substrate. While there is no band folding in the experimental band structure, additional super-periodicity is evident in low energy electron diffraction measurements, suggesting the emergence of a transition layer with crystal symmetry evolving from the SrTiO3 substrate to the SrIrO3(001) surface. Our study sheds light on the misfit relaxation mechanism in epitaxial SrIrO3 thin films in the orthorhombic phase, which is metastable in bulk.
