Events at Physics
We show that spin fluctuations affect both the scattering rate and the effective plasma frequency. Interestingly, the anisotropy in the effective scattering rate is antagonistic to the anisotropy induced in the effective plasma frequency and can become comparable near the nematic transition temperature. As a result, the ac conductivity may seem to be dominated by an effective plasma frequency anisotropy, although the dc conductivity is actually determined solely by the scattering rate anisotropy. Our results agree qualitatively with recent experiments in detwinned iron pnictides, and reveal an unavoidable entanglement between scattering rate anisotropy and plasma frequency anisotropy caused by spin fluctuations.