Bulk vs. surface effects in ARPES experiment from La2/3Sr1/3MnO3 thin films
Experiments directly probing the electronic states using angle-resolved photoemission (ARPES) were carried out on La2/3Sr1/3MnO3 in order to elucidate its electronic properties. ARPES is a surface sensitive technique where bulk and surface states are usually both present. We present high-resolution ARPES studies in the (1 0 0) and (1 1 0) mirror planes and compare them with simulated ARPES based on GGA + U band structure calculations. In the (1 1 0) mirror plane we identify surface umklapps accounted by (root 2 x root 2)R45 degrees surface reconstruction which couple to bulk electronic states. As predicted by the simulated spectra there is additional spectral intensity at the Fermi level detected in ARPES data due to k(perpendicular to)-broadening effects in the photoemission final states. We demonstrate that this additional spectral intensity is a convenient spectral marker for determination of the k(F) Fermi momenta. (C) 2010 Elsevier B.V. All rights reserved.