Saturation field of frustrated chain cuprates: broad regions of predominant interchain coupling

TL;DR

This paper introduces a thermodynamic method to accurately determine interchain coupling in frustrated spin systems from saturation field measurements, revealing complex phase diagrams and applying it to specific cuprates.

Contribution

It presents a novel, precise approach combining theoretical and experimental techniques to extract interchain coupling from saturation fields in frustrated spin chains.

Findings

H_s is primarily determined by interchain coupling in studied materials.

Predicted H_s of approximately 61 T for Y2Ca2Cu5O10.

Measured H_s of about 55 T for Li2CuO2 indicating weak interchain coupling.

Abstract

An efficient and precise thermodynamic method to extract the interchain coupling (IC) of spatially anisotropic 2D or 3D spin-1/2 systems from their empirical saturation field H_s (T=0) is proposed. Using density-matrix renormalization group, hard-core boson, and spin-wave theory we study how H_s is affected by an antiferromagnetic (AFM) IC between frustrated chains described in the J_1-J_2-spin model with ferromagnetic 1st and AFM 2nd neighbor in-chain exchange. A complex 3D-phase diagram has been found. For Li2CuO2 and Y2Ca2Cu5O10, we show that H_s is solely determined by the IC and predict H_s approx 61 T for the latter.Using H_s approx 55 T from our high-field pulsed measurements one reads out a weak IC for Li2CuO2 close to that from neutron scattering.