Spin-charge disparity of polarons in organic ferromagnets

• The picture of polarons in organic ferromagnets with spin radicals is displayed.
• The charge density and spin density of the polaron do not coincide in space.
• The charge density is highly asymmetric due to the spin radicals.
• The spin density keeps nearly symmetric under spatial reflection.

Polaron formation in quasi-one-dimensional organic ferromagnets is studied based on an extended Su–Schrieffer–Heeger model combined with a Kondo term. The charge distribution of the polaron is found to be highly asymmetric under spatial reflection, due to the spin radicals. On the contrary, the spin density is nearly symmetric; the spin asymmetry introduced by the extra electron inducing the polaron formation is nearly compensated by the spin polarization of the lower-energy states. We discuss these results on the basis of real-space mean-field calculations and symmetry arguments.

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