Chemical potential shift in La(1-x)Sr(x)MnO(3): Photoemission test of the phase separation scenario

TL;DR

This study uses core-level x-ray photoemission to analyze the chemical potential shift in La(1-x)Sr(x)MnO(3), finding no macroscopic phase separation and supporting a rigid-band doping model without mass enhancement near the metal-insulator transition.

Contribution

It provides experimental evidence against macroscopic phase separation and supports the rigid-band model for hole doping in La(1-x)Sr(x)MnO(3).

Findings

Chemical potential shift is monotonic, indicating no macroscopic phase separation.

The shift aligns with the rigid-band model of doping.

No mass enhancement observed near the metal-insulator boundary.

Abstract

We have studied the chemical potential shift in La(1-x)Sr(x)MnO(3) as a function of doped hole concentration by core-level x-ray photoemission. The shift is monotonous, which means that there is no electronic phase separation on a macroscopic scale, whereas it is consistent with the nano-meter scale cluster formation induced by chemical disorder. Comparison of the observed shift with the shift deduced from the electronic specific heat indicates that hole doping in La(1-x)Sr(x)MnO(3) is well described by the rigid-band picture. In particular no mass enhancement toward the metal-insulator boundary was implied by the chemical potential shift, consistent with the electronic specific heat data.