Magnetic excitations in the S = 1/2 antiferromagnetic-ferromagnetic chain compound BaCu2V2O8 at zero and finite temperature

TL;DR

This study investigates magnetic excitations in the S=1/2 antiferromagnetic-ferromagnetic chain compound BaCu2V2O8 at various temperatures, demonstrating persistent strong correlations and the ability to predict coherent behavior in quantum magnets.

Contribution

It provides a detailed experimental and computational analysis of finite-temperature magnetic excitations in BaCu2V2O8, a model quantum magnet, showing excellent agreement with advanced theoretical methods.

Findings

Strong correlations persist at elevated temperatures.

Asymmetric lineshape of excitations observed at finite temperatures.

Quantitative agreement between experiments and computational models.

Abstract

Unlike most quantum systems which rapidly become incoherent as temperature is raised, strong correlations persist at elevated temperatures in $S=1/2$ dimer magnets, as revealed by the unusual asymmetric lineshape of their excitations at finite temperatures. Here we quantitatively explore and parameterize the strongly correlated magnetic excitations at finite temperatures using the high resolution inelastic neutron scattering on the model compound BaCu$_2$V$_2$O$_8$ which we show to be an alternating antiferromagnetic-ferromagnetic spin$-1/2$ chain. Comparison to state of the art computational techniques shows excellent agreement over a wide temperature range. Our findings hence demonstrate the possibility to quantitatively predict coherent behavior at elevated temperatures in quantum magnets.