The strength of frustration and quantum fluctuations in LiVCuO4

TL;DR

This paper investigates the magnetic properties of LiVCuO4 using a frustrated J1-J2 model, revealing the significant influence of quantum fluctuations on magnetic structure and providing new exchange parameter estimates.

Contribution

It introduces a detailed analysis of LiVCuO4's magnetic behavior using a model that accounts for frustration and quantum effects, offering refined exchange parameters.

Findings

The pitch angle phi is highly sensitive to frustration and quantum fluctuations.

The exchange ratio alpha for LiVCuO4 is approximately 0.75, differing from previous estimates.

The study compares empirical phi-values across different cuprates.

Abstract

For the 1D-frustrated ferromagnetic J_1-J_2 model with interchain coupling added, we analyze the dynamical and static structure factor S(k,omega), the pitch angle phi of the magnetic structure, the magnetization curve of edge-shared chain cuprates, and focus on LiCuVO4 for which neither a perturbed spinon nor a spin wave approach can be applied. phi is found to be most sensitive to the interplay of frustration and quantum fluctuations. For LiVCuO4 the obtained exchange parameters J are in accord with the results for a realistic 5-band extended Hubbard model and LSDA + U predictions yielding alpha=J_2/|J_1| about 0.75 in contrast to 5.5 > alpha > 1.42 suggested in the literature. The alpha-regime of the empirical phi-values in NaCu2O2 and linarite are considered, too.