Quantum melting of charge ice and non-Fermi-liquid behavior: An exact solution for the extended Falicov-Kimball model in the ice-rule limit

TL;DR

This paper presents an exact solution for a model of electrons interacting with ice-rule variables, revealing a quantum critical point and non-Fermi-liquid behavior during the melting of charge ice in a tetrahedral lattice system.

Contribution

It provides the first exact solution for the extended Falicov-Kimball model in the ice-rule limit, elucidating quantum criticality and non-Fermi-liquid phenomena.

Findings

Identification of a quantum critical point in the model

Observation of non-Fermi-liquid behavior during charge ice melting

Comparison with pyrochlore-lattice numerical results

Abstract

An exact solution is obtained for a model of itinerant electrons coupled to ice-rule variables on the tetrahedron Husimi cactus, an analogue of the Bethe lattice of corner-sharing tetrahedra. It reveals a quantum critical point with the emergence of non-Fermi-liquid behavior in melting of the "charge ice" insulator. The electronic structure is compared with the numerical results for the pyrochlore-lattice model to elucidate the physics of electron systems interacting with the tetrahedron ice rule.