Ferrimagnetism in the organic polymeric Hubbard model: Quantum Monte Carlo simulation

Abstract

The ground-state properties of organic polymers are studied by means of the quantum Monte Carlo simulation. The polymer doped by transition-metal impurities at every other radical site of the chain is described by the quasi-one-dimensional polymeric Hubbard chain. The topological structure of the chain possesses a flat-band structure of the energy band. The spin-spin correlation function and the static magnetic susceptibility are investigated in the case of half filling. Our analysis shows that the on-site Coulomb repulsions in the chain and/or in the radical lead to the coexistence of ferromagnetic and antiferromagnetic order, i.e., the ferrimagnetic order. The on-site Coulomb repulsion (U d) of electrons at the radicals plays a more significant role in stabilizing the ferromagnetic order than that (U) on the chain does, while U has a stronger impact on the antiferromagnetic order. © 1999 The American Physical Society.