Heavy-fermion spin liquid in the strong hybridization limit of the finite-U Anderson lattice model

TL;DR

This paper predicts a novel heavy-fermion spin liquid phase in the strong hybridization limit of the finite-U Anderson lattice model, characterized by a symmetric Mott insulator with heavy fermions, distinct from fractionalized Fermi liquids.

Contribution

It introduces a new heavy-fermion spin liquid phase in the Anderson lattice model and distinguishes it from known fractionalized Fermi liquids, with a proposed variational wave function for validation.

Findings

Identification of a heavy-fermion spin liquid phase in the model

Demonstration that this phase is a symmetric Mott insulator

Discussion of the phase's stability against magnetic and gauge fluctuations

Abstract

Studying the finite-U Anderson lattice model in the strong hybridization limit, we find a heavy-fermion spin liquid phase, where both conduction and localized fermions are strongly hybridized to form heavy fermions but this heavy-fermion phase corresponds to a symmetric Mott insulating state owing to the presence of charge gap, resulting from large Hubbard-U interactions in localized fermions. We show that this heavy-fermion spin liquid phase differs from the "fractionalized" Fermi liquid state, where the latter corresponds to a metallic state with a small Fermi surface of conduction electrons while localized fermions decouple from conduction electrons to form a spin liquid state. We discuss the stability of this anomalous spin liquid phase against antiferromagnetic ordering and gauge fluctuations, in particular, instanton effects associated with confinement of slave particles. Furthermore, we propose a variational wave function to check its existence from the microscopic model.