Angle-resolved photoemission spectroscopy (ARPES) is a powerful technique for the study of electronic structure, but it lacks a direct ability to study buried interfaces between two materials. We address this limitation by combining ARPES with soft x-ray standing-wave (SW) excitation (SWARPES), in which the SW profile is scanned through the depth of the sample. We have studied the buried interface in a prototypical magnetic tunnel junction La0.7Sr0.3MnO3/SrTiO3. Depth- and momentum-resolved maps of Mn 3d eg and t2g states from the central, bulk-like and interface-like regions of La0.7Sr0.3MnO3 exhibit distinctly different behavior consistent with a change in the Mn bonding at the interface. We compare the experimental results to state-of-the-art density-functional and one-step photoemission theory, with encouraging agreement that suggests wide future applications of this technique.
@article{arxiv.1309.2022,
title = {Momentum-resolved electronic structure at a buried interface from soft x-ray standing-wave angle-resolved photoemission},
author = {A. X. Gray and J. Minár and L. Plucinski and M. Huijben and A. Bostwick and E. Rotenberg and S. -H. Yang and J. Braun and A. Winkelmann and G. Conti and D. Eiteneer and A. Rattanachata and A. A. Greer and J. Ciston and C. Ophus and G. Rijnders and D. H. A. Blank and D. Doennig and R. Pentcheva and C. M. Schneider and H. Ebert and C. S. Fadley},
journal= {arXiv preprint arXiv:1309.2022},
year = {2015}
}