Refined structure and properties of the layered mott insulator bacos2

Abstract

BaCoS2 is orthorhombic Cmma a = 6.4413(3) Å, b = 6.4926(3) Å, c = 8.9406(3) Å, and is closely related to BaNiS2, which contains Ni-S layers separated by rock salt BaS sheets. Crystals were grown from the melt by slow cooling from 1050 to 950°C. The sulfur atoms in the Co-S layers have very anisotropic thermal displacement parameters, possibly indicating that these sulfurs are actually in a double well potential centered at a high symmetry position in the space group Cmma . BaCoS2 is found to be a paramagnetic semiconductor (Mott insulator). The magnetic properties indicate that BaCoS2 undergoes a transformation at 300 K, which is likely due to the onset of antiferromagnetic order. © 1994 Academic Press, Inc.