paper

Antiferromagnetic Phases of One-Dimensional Quarter-Filled Organic Conductors

arXiv:cond-mat/9704038 · doi:10.1143/JPSJ.66.1249

Abstract

The magnetic structure of antiferromagnetically ordered phases of quasi-one-dimensional organic conductors is studied theoretically at absolute zero based on the mean field approximation to the quarter-filled band with on-site and nearest-neighbor Coulomb interaction. The differences in magnetic properties between the antiferromagnetic phase of (TMTTF) $_{2}$ X and the spin density wave phase in (TMTSF) $_{2}$ X are seen to be due to a varying degrees of roles played by the on-site Coulomb interaction. The nearest-neighbor Coulomb interaction introduces charge disproportionation, which has the same spatial periodicity as the Wigner crystal, accompanied by a modified antiferromagnetic phase. This is in accordance with the results of experiments on (TMTTF) $_{2}$ Br and (TMTTF) $_{2}$ SCN. Moreover, the antiferromagnetic phase of (DI-DCNQI) $_{2}$ Ag is predicted to have a similar antiferromagnetic spin structure.

8 pages, LaTeX, 4 figures, uses jpsj.sty, to be published in J. Phys. Soc. Jpn. 66 No. 5 (1997)