Tetrahedra system Cudaca: high-temperature manifold of molecular configurations governing low-temperature properties

TL;DR

The paper investigates the Cudaca system of Cu2+ tetrahedra, revealing that its low-temperature magnetic properties are influenced by a high-temperature manifold of molecular configurations, combining theoretical calculations and experimental data.

Contribution

It uncovers the complex interplay of magnetic exchange, electron delocalization, and molecular vibrations in Cudaca, highlighting the role of high-temperature configurations in low-temperature behavior.

Findings

Experimental data only partly explained by theoretical models

Low-temperature properties governed by high-temperature molecular configurations

Complex interplay between magnetic exchange and molecular vibrations

Abstract

The Cudaca system composed of isolated Cu2+ S=1/2 tetrahedra with antiferromagnetic exchange should exhibit properties of a frustrated quantum spin system. ab initio density functional theory calculations for electronic structure and molecular dynamics computations suggest a complex interplay between magnetic exchange, electron delocalization and molecular vibrations. Yet, extensive experimental characterization of Cudaca by means of synchrotron x-ray diffraction, magnetization, specific heat and inelastic neutron scattering reveal that properties of the real material can be only partly explained by proposed theoretical models as the low temperature properties seem to be governed by a manifold of molecular configurations coexisting at high temperatures.