We study the electronic and magnetic structures of the newly-discovered compound KCr3As3. The non-magnetic state has five Fermi surface sheets involving respectively three quasi-one-dimensional and two three-dimensional energy bands. However, the ground state is magnetic, exhibiting a novel interlayer antiferromagnetic order where the basic block-spin state of a unit Cr triangle retains a high spin magnitude. Moreover, its Fermi surface involves three one-dimensional sheets only, providing evidence for local moments in this compound due to the reduced dimensionality. By fitting a twisted spin tube model the magnetic frustrations caused by local moments are found to be relaxed, leading to gapless spin excitations. A frustration-induced transition to the disordered low block-spin state is expected upon increasing the intralayer exchange interaction.
@article{arxiv.1505.06801,
title = {Reduced Dimensionality and Magnetic Frustration in KCr$_3$As$_3$},
author = {Chao Cao and Hao Jiang and Xiao-Yong Feng and Jianhui Dai},
journal= {arXiv preprint arXiv:1505.06801},
year = {2016}
}