Comment on "Direct evidence for hidden one-dimensional Fermi surface of hexagonal K0.25WO3"

We comment a recent work titled "Direct evidence for hidden one-dimensional Fermi surface of hexagonal K0.25WO3". In this paper the authors report photoemission and theoretical results on the K0.25WO3 system which led them to propose that a Charge Density Wave (CDW), associated with hidden one-dimensional bands, was responsible for the well known resistivity anomaly in such system. In the present comment we report the results of a first principles density functional theory (DFT) study showing that there are no one-dimensional bands as suggested by these authors

Magnetism and Charge ordering in TMTTF2_2-PF6_6 organic crystals

Using a combination of Density Functional Theory, mean-field analysis and exact diagonalization calculations we reveal the emergence of a dimerized charge ordered state in TMTTF$_2$-PF$_6$ organic crystal. The interplay between charge and spin order leads to a rich phase diagram. Coexistence of charge ordering with a structural dimerization results in a ferroelectric phase, which has been observed experimentally. The tendency to the dimerization is magnetically driven revealing TMTTF$_2$-PF$_6$ as a multiferroic material