The resistivity of rare earth impurities diluted in Lanthanum, Part I

Abstract

We study the temperature-independent resistivity of rare-earth magnetic impurities (Gd, Tb, Dy) and the non-magnetic impurity (Lu) diluted in double hexagonal close-packed (dhcp) lanthanum. We model the system as a two-band system, where s-electrons perform conduction while d-electrons entirely screen the charge differences induced by impurities. Using the T-matrix formalism derived from the Dyson equation, we obtain an expression for resistivity. Since electronic properties are highly sensitive to band structure, we examine two types: a simplified “parabolic” band structure and a more realistic one obtained through first-principles calculations using VASP. Our results indicate that the exchange parameters, represented as cross products, significantly influence the magnitude of the spin resistivity term. Furthermore, we find that the role of band structure in resonant scattering and the formation of virtual bound states depends on the specific band structure employed. Additionally, our study addresses the effects of translational symmetry breaking and the excess charge introduced by rare-earth impurities on resistivity.