Abstract
We investigate the electronic and magnetic properties of the frustrated triangular-lattice antiferromagnets CsCuCl and CsCuBr in the framework of density functional theory. Analysis of the exchange couplings and using the available x-ray structural data corroborates the values obtained from experimental results for CsCuBr but not for CsCuCl. In order to understand this discrepancy, we perform a detailed study of the effect of structural optimization on the exchange couplings of CsCuCl employing different exchange-correlation functionals. We find that the exchange couplings depend on rather subtle details of the structural optimization and that only when the insulating state (mediated through spin polarization) is present in the structural optimization, we do have good agreement between the calculated and the experimentally determined exchange couplings. Finally, we discuss the effect of interlayer couplings as well as longer-ranged couplings in both systems.
2 More- Received 3 September 2010
DOI:https://doi.org/10.1103/PhysRevB.83.125126
©2011 American Physical Society