Nematic state stabilized by off-site Coulomb interaction in iron-based superconductors

Xiao-Jun Zheng; Zhong-Bing Huang; Da-Yong Liu; Liang-Jian Zou

doi:10.1103/PhysRevB.92.085109

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Nematic state stabilized by off-site Coulomb interaction in iron-based superconductors

Xiao-Jun Zheng, Zhong-Bing Huang, Da-Yong Liu, Liang-Jian Zou

DOI 10.1103/PhysRevB.92.085109 · Physical Review B

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Abstract

Using a variational Monte Carlo method, we investigate the nematic state in iron-based superconductors based on the three-band Hubbard model. Our results demonstrate that the nematic state, formed by introducing an anisotropic hopping order into the projected wave function, can arise in the underdoped regime by an off-site Coulomb interaction V induced d-wave Pomeranchuk instability. An analysis of V in momentum space indicates that the interaction between electrons around (π,0) and (0,π) points is crucial for the formation of the nematic state. The resulting anisotropic kinetic energy and spin correlation, as well as unequal occupation of dxz and dyz orbitals, are all suppressed upon electron doping, which are consistent with the doping dependence of intrinsic anisotropy revealed by optical spectrum measurement and angle-resolved photoemission spectroscopy.