X-ray photoemission spectrum, electronic structure, and magnetism of UCu$_2$Si$_2$

Abstract

The room temperature X-ray photoemission spectrum of the ferromagnetic compound UCu$_2$Si$_2$ (T$_C$ = 100 K) was measured using an Al K$_{\alpha}$ source. Related theoretical spectra were computed from densities of electronic states obtained in the local density approximation (LDA), the generalized gradient approximation (GGA), and using the GGA+U method. The calculated spectrum is in a good agreement with the experimental one. The spin polarized calculations based on the GGA+U approach as well as GGA/LSDA with orbital polarization (OP) corrections taken into account provide values of the total magnetic moment in reasonable agreement with the experimental values ranging between 1.6 and 2.0 $\mu_B$/U atom.