Comparative study between two quantum spin systems and
S. N. Bose National Centre for Basic Sciences
JD Block, Sector 3, Salt Lake City, Kolkata 700098, India
2 Fakultät 7, Theoretische Physik, University of the Saarland 66041 Saarbrücken, Germany
Accepted: 22 July 2002
We have performed an ab initio study of the electronic structure of two isostructural quantum spin systems, and , which have recently attracted much attention due to their unconventional magnetic properties. Our first-principles analysis shows unambiguously the role of , as opposed to structural differences between the two compounds, in making a strongly coupled dimer system compared to which shows a weakly coupled dimer behavior. Good agreement with the existing analysis of inelastic neutron scattering results has been observed.
PACS: 75.10.Jm – Quantized spin models / 75.30.Et – Exchange and superexchange interactions / 71.20.-b – Electron density of states and band structure of crystalline solids
© EDP Sciences, 2002