Singlet-triplet Hamiltonian for spin excitation in the Kondo-insulator

TL;DR

This paper introduces an effective singlet-triplet Hamiltonian within the Anderson model to analytically study the dynamic magnetic susceptibilities and spin excitation spectrum in Kondo insulators like YbB12.

Contribution

It presents a novel analytical approach using a singlet-triplet Hamiltonian to describe spin excitations and their dispersion in Kondo insulators, incorporating collective f-d excitations.

Findings

Describes three-level spin excitation spectrum with specific dispersion.

Introduces small radius singlet and triplet collective f-d excitations.

Models low- and high-energy spin bands in YbB12.

Abstract

Within the framework of periodic asymmetric Anderson model for Kondo isoulators an effective singlet-triplet Hamiltonian with indirect antiferromagnetic f-f exchange interaction is introduced which allows to study analytically the dynamic magnetic susceptibilities of f-electrons. The approach allows to describe the three-level spin excitation spectrum with a specific dispersion in $YbB_{12}$. Distinctive feature of the consideration is the introduction of small radius singlet and triplet collective f-d excitations which at movement on a lattice form low - and high-energy spin bands.