Strong Correlations in Electron Doped Phthalocyanine Conductors Near Half Filling

We propose that electron doped nontransition metal phthalocyanines such as ZnPc and MgPc, similar to those very recently reported, should constitute novel strongly correlated metals. Because of orbital degeneracy, Jahn-Teller coupling, and Hund’s rule exchange, and with a large on-site Coulomb repulsion, these molecular conductors should display, particularly near half filling at two electrons/molecule, very unconventional properties, including Mott insulators, strongly correlated superconductivity, and other intriguing phases.

Figure 1

Density functional electronic band structure of undoped $\alpha$ structure MgPc. The molecular stack direction is $\Gamma -Y$. The crystal structure was taken from Ref. 24. The monoclinic cell ($a=26.29$, $b=3.818$, $c=23.92Å$, $\beta =94.6$) contains four molecules and has symmetry $C2/n$.