Characteristic Energy of the Coulomb Interactions and the Pileup of States

TL;DR

This paper investigates Coulomb interaction effects in La1.28Sr1.72Mn2O7 crystals through tunneling data, revealing a characteristic energy dependence and a pileup of states, suggesting possible universal behavior.

Contribution

It provides experimental evidence of Coulomb interaction effects and state pileup in manganite crystals, confirmed by tunneling and photoemission data.

Findings

Density of states shows √E dependence due to Coulomb interactions.

Most states are removed near the Fermi level and pile up between 40-130 meV.

Results suggest possible universal behavior of Coulomb effects.

Abstract

Tunneling data on $\mathrm{La_{1.28}Sr_{1.72}Mn_2O_7}$ crystals confirm Coulomb interaction effects through the $\sqrt{\mathrm{E}}$ dependence of the density of states. Importantly, the data and analysis at high energy, E, show a pileup of states: most of the states removed from near the Fermi level are found between ~40 and 130 meV, from which we infer the possibility of universal behavior. The agreement of our tunneling data with recent photoemission results further confirms our analysis.