The origin of the electronic nematicity and its remarkable material dependence are famous longstanding unsolved issues in Fe-based superconductors. To attack these issues, we focus on the in-plane anisotropy of the resistivity: In the nematic state in FeSe, the relation ρx>ρy holds, where ρx(y) is the resistivity along the longer (shorter) Fe-Fe axis. In contrast, the opposite anisotropy ρx<ρy is realized in other undoped Fe-based superconductors. Such nontrivial material dependence is naturally explained in terms of the strongly orbital-dependent inelastic quasiparticle scattering realized in the orbital-ordered state. The opposite anisotropy between FeSe (ρx>ρy) and other undoped compounds (ρx<ρy) reflects the difference in the number of hole pockets. We also explain the large in-plane anisotropy of the thermoelectric power in the nematic state.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics