Gapped electron liquid state in the symmetric Anderson lattice, Kondo insulator state

TL;DR

This paper investigates the Kondo insulator state in the symmetric Anderson lattice using a mean field approach, revealing a gapped electron liquid with Majorana-like properties and its behavior under magnetic fields.

Contribution

It introduces a novel mean field framework that describes the Kondo insulator as a gapped electron liquid without artificial symmetry breaking.

Findings

Kondo insulator state forms in a double cell lattice.

The electron liquid behaves like a gapless Majorana spin liquid.

The gap closes at a critical magnetic field.

Abstract

The Kondo insulator state (KIS) realized in the symmetric Anderson model at half filling is studied in the framework of a mean field approach. It is shown that the state of the Kondo insulator is realized in a lattice with a double cell and a gapped electron liquid behaves like a gapless Majorana spin liquid. The local moments of d-electrons form a static $Z_2$-field in which band electrons move. The gap value in the quasi-particle excitations spectrum decreases with increasing an external magnetic field and closes at its critical value. The behavior of an electron liquid is studied for an arbitrary dimension of the model. The proposed approach leads to the description of KIS without the need to resort to artificial symmetry breaking to alternative understanding of the physical nature of this phase state.