Predominance of z2-orbitals at the surface of both hole- and electron-doped manganites.

The electronic properties of hole- and electron-doped manganites were probed by a combination of x-ray absorption and photoemission spectroscopies. Hole-doped La 0.7 Ba 0.3 MnO 3 and electron-doped La 0.7 Ce 0.3 MnO 3 thin films were epitaxially grown on SrTiO 3 substrates by means of pulsed laser deposition. Ex-situ x-ray diffraction demonstrated the substrate/film epitaxy relation and in-situ low energy electron diffraction provided evidence of high structural order of film surfaces. By combining synchrotron x-ray absorption and x-ray photoemission spectroscopy, evidence of Mn ions into a 2+ state as a result of the Ce 4 + substitution in the electron-doped manganites was provided. Angular resolved photo-emission spectroscopy (ARPES) results showed a predominance of z2-orbitals at the surface of both hole- and, unexpectedly, electron-doped manganites thus questioning the validity of the commonly accepted scenario describing the electron filling in manganites' 3d orbitals in oxide manganites. The precise determination of the electronic and orbital properties of the terminating layers of oxide manganites paves the way for engineering multi-layered heterostructures thus leading to novel opportunities in the field of quantum electronics. • The orbital character of surface electronic states of oxide manganites was identified • Epitaxial hole- (electron) doped La 0.7 (Ba,Ce) 0.3 MnO 3 thin films were grown by PLD • XAS and XPS on in-situ transferred samples provided evidence of a Ce 4 + in LCeMO • ARPES data always indicated a z2-orbital occupation in both LBMO and LCeMO • Our results are at odds with the common description of electron filling in 3d orbitals. [ABSTRACT FROM AUTHOR]