Optical conductivity and Raman scattering of iron superconductors

Abstract

We discuss how to analyze the optical conductivity and Raman spectra of multiorbital systems using the velocity and the Raman vertices in a similar way Raman vertices were used to disentangle nodal and antinodal regions in cuprates. We apply this method to iron superconductors in the magnetic and nonmagnetic states, studied at the mean-field level. We find that the anisotropy in the optical conductivity at low frequencies reflects the difference between the magnetic gaps at the X and Y electron pockets. Both gaps are sampled by Raman spectroscopy. We also show that the Drude weight anisotropy in the magnetic state is sensitive to small changes in the lattice structure.

Magnetic interactions in iron superconductors: A review

“…III A for U onset < U < U * mag . Interestingly, this nesting-like region is not present in the magnetic phase diagram calculated with the tight-binding corresponding to a squashed FeAs tetrahedra, with a Fermi surface characterised by an enhanced ellipticity of the electron pockets and lack of nesting [107,219].…”

“…The spectroscopic properties of the Hartree-Fock magnetic state, such as optical conductivity or Raman scattering [104,145,219], are mostly sensitive to the size of the magnetic gap which is directly related to the magnetic moment. Therefore the spectrum in the magnetic orbital differentiation region could be significantly different to Hartree-Fock predictions if temporal fluctuations are included in the calculations and such modifications could alter the conclusions regarding the region of parameters compatible with experimental results.…”

“…These transitions are based in the velocity and Raman vertices studied in Ref. [219] and depend on the symmetry of the orbitals involved in the interband transitions. The dependence on k-space reflects the underlying lattice [219].…”

“…[219] and depend on the symmetry of the orbitals involved in the interband transitions. The dependence on k-space reflects the underlying lattice [219]. This observation can help interpret optical and Raman data in the magnetic state.…”

Raman resonance in iron-based superconductors: The magnetic scenario

“…[1][2][3][4][5][6][7][8]). The subject of this paper is the theoretical analysis of the features in Raman scattering revealed by polarization-sensitive Raman spectroscopy in the normal and the superconducting states of Fe-based materials NaFe 1−x Co x As [9], AFe 2 As 2 , A =Eu,Sr [10 and 11], and Ba(Fe 1−x Co x ) 2 As 2 [12 and 13].…”