Phase transitions in a frustrated biquadratic Heisenberg model with coupled orbital degree of freedom for iron-based superconductors

Abstract

In this work, we study a biquadratic Heisenberg model with coupled orbital degree of freedom using Monte Carlo simulation in order to investigate the phase transitions in iron-based superconductors. The antiferro-quadrupolar state, which may be related to the magnetism of FeSe [Phys. Rev. Lett. 115, 116401 (2015)], is stabilized by the anisotropic biquadratic interaction induced by a ferro-orbital-ordered state. It is revealed that the orbital and nematic transitions occur at the same temperature for all the cases, supporting the mechanism of the orbital-driven nematicity as revealed in most recent experiments [Nat. Mater. 14, 210 (2015)]. In addition, it is suggested that the orbital interaction may lead to the separation of the structural and magnetic phase transitions as observed in many families of iron pnictides.

20 pages, 7 figures, to be published in Physical Review B

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Cited by in corpus (2)

• Possible Nematic Spin Liquid in Spin-$1$ Antiferromagnetic System on the Square Lattice: Implication for the Nematic Paramagnetic State of FeSe
• Influence of the biquadratic exchange interaction in the classical ground state magnetic response of the antiferromagnetic icosahedron