Raman spectroscopy as a probe of pairing symmetry in iron based superconductors

TYPECondensed Matter Seminar
Speaker:Maxim Khodas
Location:Lidow Nathan Rosen (300)

I will start with review of Raman data on iron chalcogenides and pnictide high-Tc superconductors.

Below Tc a sharp well defined in-gap modes are observed for cross polarized Raman beams.

Next I constrain the possible pairing symmetry relying on this data as well as ARPES, and neutron scattering.

The resulting picture is discussed  leading to the sign-changing s-wave order parameter consistent with the data.

The in-gap modes are interpreted as Bardasis-Schrieffer and particle-hole excitons respsectively.

I conclude with the summary followed by a possible explanation of the normal state data on parent compounds, AFe2As2, with A=Sr,Eu.