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

TL;DR

This study uses density functional theory to analyze the structural, electronic, and magnetic properties of $eta$-U/W(110) thin films, revealing how U-W interlayer spacing and magnetic moments vary with film thickness.

Contribution

It provides a detailed theoretical investigation of the structural and magnetic properties of $eta$-U/W(110) thin films, highlighting the effects of film thickness and substrate interactions.

Findings

U-W interlayer spacing expands by 14% in 1U/7W(110)

Magnetic moments are enhanced at the interface and suppressed at the surface with increasing U layers

Density of states near Fermi level is dominated by 5f U states

Abstract

Structural, electronic and magnetic properties were calculated for the optimized $\alpha$-U/W(110) thin films (TFs) within the density functional theory. Our optimization for 1U/7W(110) shows that the U-W vertical interlayer spacing (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 enhanced from zero for the bulk of $\alpha$-U to 1.4 $\mu_B$ and -0.4 $\mu_B$ at the interface 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 our obtained 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 and suppression of the MMs and shows that the total DOS, in agreement with experiment, is dominated in the vicinity of Fermi level by the 5f U states. Proximity and mismatch effects of the nonmagnetic W(110) substrate were assessed and found to be important for this system.