Pseudogap behavior in Pr$_{0.5}$Sr$_{0.5}$MnO$_3$: A photoemission study

TL;DR

This study investigates the electronic structure of Pr$_{0.5}$Sr$_{0.5}$MnO$_3$ across different magnetic phases, revealing a pseudogap related to electron-phonon interactions and Jahn Teller polarons, with implications for charge localization.

Contribution

It provides the first detailed photoemission analysis of pseudogap behavior in Pr$_{0.5}$Sr$_{0.5}$MnO$_3$ across its phase transitions, highlighting surface charge dynamics.

Findings

Presence of an 80 meV pseudogap in PMM and FMM phases

Finite Fermi level intensity in the AFMI phase

Pseudogap linked to Jahn Teller polarons and electron-phonon interactions

Abstract

The valence band electronic structure of Pr$_{0.5}$Sr$_{0.5}$MnO$_3$ has been investigated across its paramagnetic metallic (PMM) - ferromagnetic metallic (FMM) - antiferromagnetic insulator (AFMI) transition. Using surface sensitive high resolution photoemission we have conclusively demonstrated the presence of a pseudogap of magnitude 80 meV in the near Fermi level electronic spectrum in the PMM and FMM phases and finite intensity at the Fermi level in the charge ordering (CO)-AFMI phase. The pseudogap behavior is explained in terms of the strong electron-phonon interaction and the formation of Jahn Teller (JT) polarons, indicating the charge localizations. The finite intensity at the Fermi level in the insulating phase showed a lack of charge ordering in the surface of the Pr$_{0.5}$Sr$_{0.5}$MnO$_3$ samples.