Momentum-resolved electronic structure at a buried interface from soft X-ray standing-wave angle-resolved photoemission

Abstract

Angle-resolved photoemission spectroscopy (ARPES) is a powerful technique for\nthe study of electronic structure, but it lacks a direct ability to study\nburied interfaces between two materials. We address this limitation by\ncombining ARPES with soft x-ray standing-wave (SW) excitation (SWARPES), in\nwhich the SW profile is scanned through the depth of the sample. We have\nstudied the buried interface in a prototypical magnetic tunnel junction\nLa0.7Sr0.3MnO3/SrTiO3. Depth- and momentum-resolved maps of Mn 3d eg and t2g\nstates from the central, bulk-like and interface-like regions of La0.7Sr0.3MnO3\nexhibit distinctly different behavior consistent with a change in the Mn\nbonding at the interface. We compare the experimental results to\nstate-of-the-art density-functional and one-step photoemission theory, with\nencouraging agreement that suggests wide future applications of this technique.\n