+1 Recommend
0 collections
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Diverse Exotic Orders and Fermiology in Fe-based Superconductors: A Unified Mechanism for \(B_{1g}/B_{2g}\) Nematicity in FeSe/(Cs,Rb)Fe\(_2\)As\(_2\) and Smectic Order in BaFe\(_2\)As\(_2\)


      Read this article at

          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.


          Rich nematic/smectic orders in Fe-based superconductors are important unsolved problem in the strongly correlated electron systems. A unified understanding for these rich orders has been investigated for the last decade. In this article, we explain the \(B_{1g}\) symmetry nematic transition in FeSe\(_{1-x}\)Te\(_x\), the \(B_{2g}\) symmetry nematicity in AFe\(_2\)As\(_2\) (A=Cs, Rb), and the smectic state in BaFe\(_2\)As\(_2\) based on the same framework. We investigate the quantum interference mechanism between spin fluctuations, by developing the density wave equation with the self-energy correction. In this mechanism, the observed rich variety of nematic/smectic orders are naturally understood, depending on the characteristic shape and topology of FS of each compound. (i) In FeSe\(_{1-x}\)Te\(_x\), each FS is very small and the dxy-orbital hole pocket is below the Fermi level. Then, small spin fluctuations on three dxz, dyz, and dxy orbitals cooperatively lead to the \(B_{1g}\) nematic order without magnetization. The experimental Lifshitz transition below the nematic transition temperature \((T_S)\) is naturally reproduced. (ii) In BaFe\(_2\)As\(_2\), the dxy-orbital hole pocket emerges around M point, and each FS is relatively large. Then, the strong spin fluctuations due to the dxy-orbital nesting give rise to the \(B_{1g}\) nematic order and the smectic order, and the latter transition temperature (\(T^*\)) exceeds the former one \(T_S\). (iii) In heavily hole-doped AFe\(_2\)As\(_2\), the large dxy-orbital hole pocket and the four tiny Dirac pockets appear due to the hole-doping. Then, the \(B_{2g}\) nematic bond order emerges on the dxy-orbital hole pocket due to the same interference mechanism. The present spin-fluctuation interference mechanism provides a unified explanation why the nematic/smectic orders in Fe-based superconductors are so rich, based on the well established fermiology of Fe-based superconductors.

          Related collections

          Author and article information

          08 April 2022


          Custom metadata
          22 pages, 14 figures
          cond-mat.str-el cond-mat.supr-con

          Condensed matter
          Condensed matter


          Comment on this article