Effective quantum pseudospin-1/2 model for Yb pyrochlore oxides

TL;DR

This paper derives an effective quantum pseudospin-1/2 model for Yb pyrochlore oxides, capturing their magnetic interactions with strong anisotropy, based on microscopic calculations involving superexchange and dipole interactions.

Contribution

The paper presents a new microscopic derivation of the pseudospin-1/2 Hamiltonian for Yb pyrochlore oxides, incorporating exchange anisotropy from superexchange and dipolar interactions.

Findings

The model accurately describes the atomic Kramers doublet with J^z=±1/2.

It reveals a strong exchange anisotropy in the magnetic interactions.

The Hamiltonian combines superexchange and magnetic dipole contributions.

Abstract

An effective quantum pseudospin-1/2 Hamiltonian for Yb_2TM_2O_7 (TM = Ti and Sn) is obtained in terms of the atomic Kramers ground doublet of the LS coupling and the crystalline electric field, which is almost described with J^z=\pm 1/2. It is calculated microscopically as the sum of Anderson's superexchange interaction and the magnetic dipole interaction. It is found that it shows a strong exchange anisotropy.