Nematicity, magnetic fluctuation and ferro-spin-orbital ordering in BaFe2As2 family

JOURNAL OF ALLOYS AND COMPOUNDS

卷:675

Article

Sen, Smritijit^1,2  Ghosh, Haranath^1,2 

[1] Homi Bhabha Natl Inst, Bombay 400094, Maharashtra, India

[2] Raja Ramanna Ctr Adv Technol, Ind Synchrotrons Utilizat Div, Indore 452013, India

关键词: Fe-based superconductors;    Orbital fluctuation;    Nematicity;    Spin density wave;   

DOI  :  10.1016/j.jallcom.2016.03.034

来源: Elsevier

【 摘 要 】

Through detailed electronic structure simulations we show that the electronic orbital ordering (between d(yz), and d(xz), bands) takes place due to local breaking of in -plane symmetry that generates two nonequivalent a, b directions in 122 family of Fe -based superconductors. Orbital ordering is strongly anisotropic and the temperature dependence of the corner zone orbital order maps to that of the orthorhombicity parameter. Orbital anisotropy results in two distinct spin density wave nesting wave vectors and causes inter -orbital charge and spin fluctuations. Temperature dependence of the orbital order is proportional to the nematic order and it sets in at a temperature where magnetic fluctuation starts building. Magnetic fluctuations in the orthorhombic phase is characterized through evolution of Stoner factor which reproduces experimental findings very accurately. Orbital ordering becomes strongly spin dependent in presence of magnetic interaction. Occupation probabilities of all the Fe-d-orbitals exhibit temperature dependence indicating their possible contribution in orbital fluctuation. This need to be contrasted with the usual definition of nematic order parameter (n(dxz),-n(dyz)). Relationship among orbital fluctuations, magnetic fluctuations and nematicity are established. (C) 2016 Elsevier B.V. All rights reserved.

【 授权许可】

Free