The strength of frustration and quantum fluctuations in LiVCuO₄

¹ Institute for Theoretical Solid State Physics, IFW-Dresden - Helmholtzstrasse 20, 01069 Dresden, Germany, EU
² Donostia International Physics Center (DIPC) - ES-20018 Donostia-San Sebastian, Spain, EU
³ Institut für Theoretische Physik, Universität Magdeburg - Magdeburg, Germany, EU
⁴ Institute of Physics, ASCR - Prague, Czech Republic, EU
⁵ Max-Planck-Institut für Chemische Physik fester Stoffe - Dresden, Germany, EU

^a s.l.drechsler@ifw-dresden.de

Received: 26 October 2011
Accepted: 17 April 2012

Abstract

For the 1D-frustrated ferromagnetic J₁-J₂ model with inter-chain coupling added, we analyze the dynamical and static spin structure factor S(k, ω), the pitch angle φ of the magnetic structure, the magnetization curve of edge-shared chain cuprates, and focus on LiCuVO₄=LiCuVO₄ for which neither a perturbed spinon nor a spin wave approach can be applied. φ is found to be most sensitive to the interplay of frustration and quantum fluctuations. For LiCuVO₄ the obtained J's agree with the results for a realistic 5-band extended Hubbard model and LSDA+U predictions yielding α=J₂/|J₁|≈0.75 in contrast to 5.5>α>1.42 suggested in the literature. The α-regime of the empirical φ-values in NaCu₂O₂ and linarite are considered, too.