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

Abstract

Structural, electronic and magnetic properties were calculated for the optimized α-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 α-U to 1.4 µB and -0.4 µB 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.

First principles application for mechanical properties of Ti-doped W particles enhanced U matrix composite

“…The equilibrium primitive unit cell volumes were 0.02015 and 0.01606 nm 3 , respectively. These results were in agreement with the pseudopotential results of the others [19][20][21][22][23], as well as experimental results in Refs. [24,25].…”

“…Relaxation continues until the optimization is completed and the lowest energy interface is the reasonable distance, 0.24 nm, as listed in Table 2. According to the computational result and Zarshenas' investigation [23], a crystal orientation of W(110)/ a-U(001) was selected. Although other kinds of interface orientations between bcc-W and orthorhombic a-U can be presented, it is believed that the primary bonding can be characterized by a model as investigated in this study.…”

Mechanical properties and variation in SOC going from La to Nd in intermetallic RIn3 and RSn3 (R = La, Ce, Pr, Nd)

“…Therefore, the LaIn 3 and LaSn 3 compounds show more ductility than the remaining RIn 3 and RSn 3 compounds, which is due to the large separation between the Fermi level and the f states according to a previous study. 50 Strongly correlated systems such as lanthanides (and actinides) 39,51 which involve 4f (or 5f) orbitals have interesting physical and chemical properties, because these electrons can be localized or itinerant depending on the crystalline environment. Therefore, to understand the effects of the 4f orbitals in these compounds, the calculations are also carried out with the Hubbard potential U (GGA + U and LDA + U).…”

Ab initio studies of electric field gradients and magnetic properties of uranium dipnicties

“…According to the Hill criteria, 20 uranium based compounds with the U-U interatomic distances smaller than 3.4-3.6 Å are typically nonmagnetic with itinerant 5f states. 21 Metallic uranium is paramagnetic but shows magnetic ordering when it combines with group 5 (N, P, As, Sb, Bi) or group 6 (S, Se, Te) elements. All UX 2 (X ¼ Bi, Sb, As, P) actinide compounds are antiferromagnetic with relatively high Néel temperature.…”