Orbital- and spin-order sensitive nonlocal screening in Mn 2p X-ray photoemission of La_1−xSr_xMnO₃

Department of Mathematical Sciences, Graduate School of Engineering, Osaka Prefecture University 1-1 Gakuen-cho, Nakaku, Sakai, Osaka 599-8531, Japan

Received: 12 January 2016
Accepted: 4 May 2016

Abstract

The Mn 2p X-ray photoemission spectra (XPS) of LaMnO₃ (LMO) and hole-doped La_0.7Sr_0.3MnO₃ (LSMO) are investigated using a dp model simulating Mn 3d and O 2p electrons under the perovskite-type crystal structure. The observed 2p XPS features, especially the low-binding-energy structure (LBES) of the main line, are reproduced well using an impurity Anderson model optimized from the dp model within the dynamical mean-field approximation. The LBES in both compounds is due to the nonlocal screening (NLS) between the neighboring Mn ions in the final state, but the screening character is quite different: The NLS in LSMO directly reflects the character of the ferromagnetic metal, while that in undoped LMO the C-type orbital order between and orbitals in the ab-plane. We emphasize the directive nature of the NLS in the orbital order system, which can be a sensitive probe to the order pattern.