We investigate the physical properties and electronic structure of BaFe2-{\delta}Se3 crystals, which were grown out of tellurium flux. The crystal structure of the compound, an iron-deficient derivative of the ThCr2Si2-type, is built upon edge-shared FeSe4 tetrahedra fused into double chains. The semiconducting BaFe2-{\delta}Se3 with {\delta} \approx 0.2 ({\rho}295K = 0.18 {\Omega}\cdotcm and Eg = 0.30 eV) does not order magnetically, however there is evidence for short-range magnetic correlations of spin glass type (Tf \approx 50 K) in magnetization, heat capacity and neutron diffraction results. A one-third substitution of selenium with sulfur leads to a slightly higher electrical conductivity ({\rho}295K = 0.11 {\Omega}\cdotcm and Eg = 0.22 eV) and a lower spin glass freezing temperature (Tf \approx 15 K), corroborating with higher electrical conductivity reported for BaFe2S3. According to the electronic structure calculations, BaFe2Se3 can be considered as a one-dimensional ladder structure with a weak interchain coupling.
@article{arxiv.1110.2439,
title = {Spin Glass and Semiconducting Behavior in 1D BaFe2-{\delta}Se3 Crystals},
author = {Bayrammurad Saparov and Stuart Calder and Balazs Sipos and Huibo Cao and Songxue Chi and David J. Singh and Andrew D. Christianson and Mark D. Lumsden and Athena S. Sefat},
journal= {arXiv preprint arXiv:1110.2439},
year = {2012}
}