Unbiased access to exchange splitting of magnetic bands using the maximum entropy method

The experimental information about magnetic bands and their temperature dependence is distorted by Fermi distribution and apparatus function. The recovery of the spectral density constitutes an ill-posed inversion problem. We have invoked the maximum entropy regularization to deconvolute spin-resolved inverse photoemission data of Ni(110). The effective energy resolution is hereby improved by a factor of 5 and structures below EF, which are generally lost in inverse photoemission, are recovered. The temperature-dependent data for Ni reveal clearly a pair of spin-split bands. The splitting vanishes on approaching the Curie temperature.