Redistribution of the density of states due to Coulomb interactions in La2-2x Sr1+2x Mn2 O7

Abstract

Tunneling data on La1.28 Sr1.72 Mn2 O7 crystals confirm Coulomb interaction effects through the 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. © 2007 The American Physical Society.