Proposed low energy model Hamiltonian for spin-gapped system CuTe2O5

TL;DR

This paper derives a low-energy spin model for CuTe2O5 using first-principles calculations, revealing it as a 2D coupled spin-dimer system and comparing results with experimental data.

Contribution

The study introduces a new low-energy spin Hamiltonian for CuTe2O5 based on NMTO-downfolding, challenging previous models and providing predictions for future experiments.

Findings

CuTe2O5 is a 2D coupled spin-dimer system

The model matches magnetic susceptibility data

Predictions for magnetization and specific heat

Abstract

Using first-principles electronic structure calculations based on the Nth order muffin tin orbital (NMTO)-downfolding technique, we derived the low-energy spin model for CuTe2O5. Our study reveals that this compound is a 2D coupled spin-dimer system with the strongest Cu-Cu interaction mediated by two O-Te-O bridges. We checked the goodness of our model by computing the magnetic susceptibility with the Quantum Monte Carlo technique and by comparing it with available experimental data. We also present magnetization and specific heat results which may be compared with future experimental investigations. Our derived model is in disagreement with a recently proposed model for this compound [J. Deisenhofer et al, Phys. Rev. B,74 (2006) 174421]. The situation needs to be settled in terms of further experimental investigations.