The properties of two quantum spin chain materials, K2CuSO4Cl2 and K2CuSO4Br2, are studied by a variety of experimental techniques, including bulk measurements, neutron spectroscopy and ESR. The hierarchy of relevant terms in the magnetic Hamiltonian is established. It is shown that these two compounds feature substantial Dzyaloshinskii-Moriya (DM) interactions that are uniform within each chain, but antiparallel in adjacent chains. The result is a peculiar type of frustration of inter-chain interactions, which leads to an unusual field-temperature phase diagram.
@article{arxiv.1408.5749,
title = {Quantum spin chains with frustration due to Dzyaloshinskii-Moriya interactions},
author = {Manuel Hälg and Wolfram E. A. Lorenz and Kirill Yu. Povarov and Martin Månsson and Yurii Skourski and Andrey Zheludev},
journal= {arXiv preprint arXiv:1408.5749},
year = {2014}
}