Theoretical study of α-U/W(110) thin films from density functional theory calculations: Structural, magnetic and electronic properties

摘要

Structural, electronic and magnetic properties were calculated for theoptimized $lpha$-U/W(110) thin films (TFs) within the density functionaltheory. Our optimization for 1U/7W(110) shows that the U-W vertical interlayerspacing (ILS) is expanded by 14.0% compared to our calculated bulk W-W ILS.Spin and orbital magnetic moments (MMs) per U atom were found to be enhancedfrom zero for the bulk of $lpha$-U to 1.4 $mu_B$ and -0.4 $mu_B$ at theinterface of the 1U/7W(110), respectively. Inversely, our result for 3U/7W(110)TFs shows that the surface U-U ILS is contracted by 15.7% compared to ourobtained bulk U-U spacing. The enhanced spin and orbital MMs in the 1U/7W(110)were then found to be suppressed in 3U/7W(110) to their ignorable bulk values.The calculated density of states (DOS) corroborates the enhancement andsuppression of the MMs and shows that the total DOS, in agreement withexperiment, is dominated in the vicinity of Fermi level by the 5f U states.Proximity and mismatch effects of the nonmagnetic W(110) substrate wereassessed and found to be important for this system.