Abstract
We compute Raman scattering intensities via the lowest-order coupling to the bosonic propagator associated with orbital nematic fluctuations in a minimal model for iron pnictides. The model consists of two bands on a square lattice exhibiting four Fermi pockets and a transition from a normal to a nematic state. It is shown that the orbital fluctuations produce in the channel strong quasielastic light scattering around the nematic critical temperature , both above and below . This holds for the symmetry only below , whereas no low-energy scattering from orbital fluctuations is found in the symmetry. Due to the nematic distortion, the electron pocket at the point may disappear at low temperatures. Such a Lifshitz transition causes in the spectrum a large upward shift of spectral weight in the high-energy region, whereas no effect is seen in the other symmetries.
- Received 18 June 2013
DOI:https://doi.org/10.1103/PhysRevB.88.125120
©2013 American Physical Society