Fully relativistic description of magnetic Compton profiles with an application to $\mathrm{U}{\mathrm{Fe}}_2$

The magnetic Compton profile of $\mathrm{U}{\mathrm{Fe}}_2$ has been calculated using the spin-polarized relativistic Korringa-Kohn-Rostoker band-structure method. For this purpose a corresponding fully relativistic scheme to determine the magnetic Compton profile has been developed. This approach accounts for magnetism as well as all relativistic effects on the same footing, as it is indispensable when dealing with the electronic structure of magnetic compounds containing heavy elements. Results obtained for the magnetic Compton profile of $\mathrm{U}{\mathrm{Fe}}_2$ are found in good agreement with experimental data of Lawsonet al. An analysis of the component-resolved contributions to the magnetic Compton profile shows that there is no strict one-to-one relation to the corresponding spin moments. In addition an appreciable site-site interference contribution is found.

Figure 1

Theoretical magnetic Compton profile of $\mathrm{U}{\mathrm{Fe}}_2$ with the spin-orbit coupling included $(\mathrm{SOC}=1)$ and suppressed $(\mathrm{SOC}=0)$. The spectra have been convoluted with a Gaussian of a full width at half maximum (FWHM) $0.78\mathrm{a.u.}$ in line with the corresponding experimental data of Lawson et al. (Ref. 8).

Figure 2

The magnetic Compton profile of $\mathrm{U}{\mathrm{Fe}}_2$ (solid line) decomposed into U (open circles), Fe (open squares), and interference term (U-Fe) (open triangles) contributions. The profiles have been broadened with a Gaussian of $\mathrm{FWHM}=0.78\mathrm{a.u.}$, according to the experimental momentum resolution. The experimental data of Lawson et al. (Ref. 8) are represented by circles.

Figure 3

The partial contributions to the magnetic Compton profile of $\mathrm{U}{\mathrm{Fe}}_2$: U (circles), Fe (squares), and interference (triangles) terms resulting from the SPR-KKR calculation, together with the “Fe $3d$” (solid line), “U $5f$” (dotted line), and “$spd$” (dashed line) terms used by Lawson et al. (Ref. 8) to fit the experimental data.