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.
von der Linden, W., Donath, M., & Dose, V. (1993). Unbiased access to exchange splitting of magnetic bands using the maximum entropy method. Physical Review Letters, 71(6), 899. https://doi.org/10.1103/PhysRevLett.71.899