We use angle-resolved photoemission spectroscopy to study the doping evolution of infinite-layer Sr1−xLaxCuO2 thin films grown by molecular-beam epitaxy. At low doping, the material exhibits a dispersive lower Hubbard band typical of the superconducting cuprate parent compounds. As carriers are added to the system, a continuous evolution from charge-transfer insulator to superconductor is observed, with the initial lower Hubbard band pinned well below the Fermi level and the development of a coherent low-energy band with electron doping. This two-component spectral function emphasizes the important role that strong local correlations play even at relatively high doping levels. Electron diffraction probes reveal a p(2×2) surface reconstruction of the material at low doping levels. Using a number of simple assumptions, we develop a model of this reconstruction based on the polar nature of the infinite-layer structure. Finally, we provide evidence for a thickness-controlled transition in ultrathin films of SrCuO2 grown on nonpolar SrTiO3, highlighting the diverse structural changes that can occur in polar complex oxide thin films.
@article{arxiv.1508.03023,
title = {Doping evolution and polar surface reconstruction of the infinite-layer cuprate Sr$_{1-x}$La$_{x}$CuO$_{2}$},
author = {John W. Harter and Luigi Maritato and Daniel E. Shai and Eric J. Monkman and Yuefeng Nie and Darrell G. Schlom and Kyle M. Shen},
journal= {arXiv preprint arXiv:1508.03023},
year = {2015}
}