A low-dimensional quantum spin system separated by charge-disproportionated nonmagnetic BEST layers in (BEST)3Zn(NCS)4

Abstract

We report the structural and physical properties of a novel low-dimensional organic antiferromagnet, (BEST)₃Zn(NCS)₄, where BEST denotes bis(ethylenediseleno)tetrathiafulvalene. Single-crystal X-ray diffraction reveals that one BEST molecular layer exhibits β-type stacking, and the bond length analysis suggests the presence of a stripe-type charge-ordered phase. Furthermore, magnetization and ESR measurements indicate that the other molecular layer contains localized spins, whose spin susceptibility is well reproduced by a spin S = 1/2 alternating antiferromagnetic Heisenberg chain model. The spin subsystem is separated by nonmagnetic charge-ordered layers and closed-shell anions, exemplifying a unique design strategy for realizing a low-dimensional magnet.