Kohn anomalies in momentum dependence of magnetic susceptibility of some three-dimensional systems

TL;DR

This paper investigates the presence and characteristics of Kohn points in the electronic spectra of three-dimensional systems, revealing their influence on magnetic susceptibility and their agreement with experimental and band structure data.

Contribution

It demonstrates the existence of Kohn points in specific 3D models and analyzes their dependence on electronic concentration and wave vectors, linking theoretical predictions with experimental observations.

Findings

Kohn points exist in a wide range of electronic concentrations.

Wave vectors of susceptibility maxima depend on chemical potential.

Lines of Kohn points align with experimental data on chromium.

Abstract

We study a question of presence of Kohn points, yielding at low temperatures non-analytic momentum dependence of magnetic susceptibility near its maximum, in electronic spectum of some three-dimensional systems. In particular, we consider one-band model on face centered cubic lattice with hopping between nearest and next-nearest neighbors, which models some aspects of the dispersion of ZrZn$_2$, and the two-band model on body centered cubic lattice, modeling the dispersion of chromium. For the former model it is shown that Kohn points yielding maxima of susceptibility exist in a certain (sufficiently wide) region of electronic concentrations; the dependence of the wave vectors, corresponding to the maxima, on the chemical potential is investigated. For the two-band model we show existence of the lines of Kohn points, yielding maximum of the susceptibility, which position agrees with the results of band structure calculations and experimental data on the wave vector of antiferromagnetism of chromium.