Nature of Well-Screened State in Hard X-ray Mn 2$p$ Core-Level Photoemission of La$_{1-x}$Sr$_x$MnO$_3$ Films

TL;DR

This study uses hard x-ray photoemission spectroscopy to reveal a well-screened electronic state in La$_{1-x}$Sr$_x$MnO$_3$ films, providing insights into their bulk electronic structure and its relation to ferromagnetism and metallicity.

Contribution

It demonstrates the presence of a bulk-sensitive well-screened feature in Mn 2$p$ core-levels using HX-PES, supported by cluster model calculations including charge transfer effects.

Findings

Well-screened feature observed only in HX-PES

Feature has bulk ($ extgreater$20 Å) character

Doping and temperature dependence correlates with ferromagnetism

Abstract

Using hard x-ray (HX ; $h\nu$ = 5.95 keV) synchrotron photoemission spectroscopy (PES), we study the intrinsic electronic structure of La$_{1-x}$Sr$_x$MnO$_3$ (LSMO) thin films. Comparison of Mn 2$p$ core-levels with Soft x-ray (SX ; $h\nu$ $\sim$ 1000 eV) -PES shows a clear additional well-screened feature only in HX-PES. Take-off-angle dependent data indicate its bulk ($\ge$ 20 {\AA}) character. The doping and temperature dependence track the ferromagnetism and metallicity of the LSMO series. Cluster model calculations including charge transfer from doping induced states show good agreement, confirming this picture of bulk properties reflected in Mn 2$p$ core-levels using HX-PES.