Abstract
By the first-principles electronic structure calculations, we find that the ground state of PbO-type tetragonal -FeTe is in a bicollinear antiferromagnetic order, in which the Fe local moments () align ferromagnetically along a diagonal direction and antiferromagnetically along the other diagonal direction on the Fe square lattice. This novel bicollinear order results from the interplay among the nearest, the next-nearest, and the next-next-nearest neighbor superexchange interactions, mediated by Te band. In contrast, the ground state of -FeSe is in a collinear antiferromagnetic order, similar to those in LaFeAsO and . This finding sheds new light on the origin of magnetic ordering in Fe-based superconductors.
- Received 15 October 2008
DOI:https://doi.org/10.1103/PhysRevLett.102.177003
©2009 American Physical Society