Antiferromagnetism and hot spots in CeIn$_3$

TL;DR

This paper explains the large effective mass enhancement at hot spots in CeIn$_3$ near its antiferromagnetic quantum critical point by analyzing Fermi surface topology changes and magnetic field effects, aligning well with experimental observations.

Contribution

It reveals how antiferromagnetic ordering causes topological Fermi surface changes that lead to mass divergence and hot spot effects, providing a theoretical explanation for experimental data.

Findings

Logarithmic divergence of effective mass near hot spots.

Fermi surface topology changes at AFM transition.

Agreement of phase diagram with experimental results.

Abstract

Enormous mass enhancement at ''hot spots'' on the Fermi surface (FS) of CeIn$_3$ has been reported at strong magnetic field near its antiferromagnetic (AFM) quantum critical point [T. Ebihara et al., Phys. Rev. Lett. 93, 246401 (2004)] and ascribed to anomalous spin fluctuations at these spots. The ''hot spots'' lie at the positions on FS where in non-magnetic LaIn$_3$ the narrow necks are protruded. In paramagnetic phase CeIn$_3$ has similar spectrum. We show that in the presence of AFM ordering its FS undergoes a topological change at the onset of AFM order that truncates the necks at the ''hot spots'' for one of the branches. Applied field leads to the logarithmic divergence of the dHvA effective mass when the electron trajectory passes near or through the neck positions. This effect explains the observed dHvA mass enhancement at the ''hot spots'' and leads to interesting predictions concerning the spin-dependence of the effective electron mass. The (T,B)-phase diagram of CeIn$_3$, constructed in terms of the Landau functional, is in agreement with experiment.