Momentum space anisotropy of electronic correlations in Fe and Ni - an analysis of magnetic Compton profiles

The total and magnetically resolved Compton profiles are analyzed within the combined density functional and dynamical mean field theory for the transition metal elements Fe and Ni. A rather good agreement between the measured and computed magnetic Compton profiles (MCPs) of Fe and Ni is obtained with the standard Local Spin Density Approximation (LSDA). By including local but dynamic many-body correlations captured by Dynamical Mean Field Theory (DMFT), the calculated magnetic Compton profile is further improved when compared with experiment. The second moment of the difference of the total Compton profiles between LSDA and DMFT, along the same momentum direction, has been used to discuss the strength of electronic correlations in Fe and Ni.