Conductivity anisotropy in the antiferromagnetic state of iron pnictides
Abstract
Recent experiments on iron pnictides have uncovered a large in-plane resistivity anisotropy with a surprising result: the system conducts better in the antiferromagnetic x direction than in the ferromagnetic y direction. We address this problem by calculating the ratio of the Drude weight along the x and y directions, Dx/Dy, for the mean-field Q=(\pi,0) magnetic phase diagram of a five-band model for the undoped pnictides. We find that Dx/Dy ranges between 0.3 < D_x/D_y < 1.4 for different interaction parameters. Large values of orbital ordering favor an anisotropy opposite to the one found experimentally. On the other hand D_x/D_y is strongly dependent on the topology and morfology of the reconstructed Fermi surface. Our results points against orbital ordering as the origin of the observed conductivity anisotropy, which may be ascribed to the anisotropy of the Fermi velocity.
Keywords
Cite
@article{arxiv.1007.3483,
title = {Conductivity anisotropy in the antiferromagnetic state of iron pnictides},
author = {B. Valenzuela and E. Bascones and M. J. Calderón},
journal= {arXiv preprint arXiv:1007.3483},
year = {2010}
}
Comments
4 pages, 3 pdf figures. Fig 1(b) changed, one equation corrected, minor changes in the text, references updated