Band Calculations for Ce Compounds with AuCu$_{3}$-type Crystal Structure on the basis of Dynamical Mean Field Theory I. CePd$_{3}$ and CeRh$_{3}$

TL;DR

This paper presents a first-principles dynamical mean field theory (DMFT) band calculation for Ce compounds with AuCu3 structure, successfully reproducing experimental spectra and elucidating temperature-dependent Fermi surface changes.

Contribution

It introduces a novel DMFT-based band calculation method incorporating crystal-field splitting, spin-orbit interaction, and virtual excitations, applied to CePd3 and CeRh3.

Findings

Successfully reproduces photoemission and magnetic spectra.

Shows Fermi surface evolution with temperature in CePd3.

Demonstrates the importance of including virtual excitations in calculations.

Abstract

Band calculations for Ce compounds with the AuCu$_{3}$-type crystal structure were carried out on the basis of dynamical mean field theory (DMFT). The auxiliary impurity problem was solved by a method named NCA$f^{2}$vc (noncrossing approximation including the $f^{2}$ state as a vertex correction). The calculations take into account the crystal-field splitting, the spin-orbit interaction, and the correct exchange process of the $f^{1} \rightarrow f^{0},f^{2}$ virtual excitation. These are necessary features in the quantitative band theory for Ce compounds and in the calculation of their excitation spectra. The results of applying the calculation to CePd$_{3}$ and CeRh$_{3}$ are presented as the first in a series of papers. The experimental results of the photoemission spectrum (PES), the inverse PES, the angle-resolved PES, and the magnetic excitation spectra were reasonably reproduced by the first-principles DMFT band calculation. At low temperatures, the Fermi surface (FS) structure of CePd$_{3}$ is similar to that of the band obtained by the local density approximation. It gradually changes into a form that is similar to the FS of LaPd$_{3}$ as the temperature increases, since the $4f$ band shifts to the high-energy side and the lifetime broadening becomes large.}