Evidence for polarons in iron pnictides of the Ln-1111 and AE-122 families

Abstract

Examination of the electrical resistivities of iron pnictides shows that they can be accounted by conduction by polarons. Their activation energies show a linear behaviour with the critical temperatures of the spin density waves (SDW), T*, as both vary with pressure. The slope matches the ratio SDW gap to T*, while the intercept can be related to the transition temperature of the lattice distortion, T0. An adapted Landau free energy predicts the observed order of the transitions, according to which is higher, T* or T0. Simple arguments favour combined Jahn-Teller antiferromagnetic bipolarons.

arXiv comment14 pages with 4 Figures

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Cited by in corpus (3)

• Interplay of magnetic and structural transitions in Fe-based pnictide superconductors
• Strong Pressure Dependent Electron-Phonon Coupling in FeSe
• Effect of tensile stress on the in-plane resistivity anisotropy in BaFe2As2