Absence of temperature dependence of the valence-band spectrum of Co2MnSi

Valence-band electronic structure of Co2MnSi has been revealed by photoelectron spectroscopy utilizing hard x-ray synchrotron radiation. We have obtained a good correspondence between experimental valence-band spectra and theoretical density of states calculated with generalized gradient aprroximation. However, no distinct temperature dependence has been observed for the experimental valence band, which requires reexamination of the explanation based on the dynamical mean-field theory for the rapid decrease in tunneling magnetoresistance ratio with increasing temperature.