Competition of exchange and crystal field interactions in cerium monopnictides and monochalcogenides

We have applied two ab initio based methods to study the dramatic change of magnetic properties across a series of strongly correlated electron system s consisting of cerium monopnictides and monochalcogenides. While, the full y ab initio method gives good results for the magnetic moments in the light er chalcogenides, it entirely fails to give, even qualitatively, the trend of their unusual magnetic behavior. On the other hand, the second approach, which explicitly takes into account the interplay between the hybridizatio n, the Coulomb exchange, and the crystal-field interactions, gives results in excellent agreement with experiment for all compounds in the series, inc luding the moment collapse from CeSb to CeTe and the trend of moments and o rdering temperatures across the series. (C) 2000 American Institute of Phys ics. [S0021-8979(00)65008-9].