Observation of incipient charge nematicity in Ba(Fe(1-x)Co(x))2As2

Phys Rev Lett. 2013 Dec 27;111(26):267001. doi: 10.1103/PhysRevLett.111.267001. Epub 2013 Dec 27.

Abstract

Using electronic Raman spectroscopy, we report direct measurements of charge nematic fluctuations in the tetragonal phase of strain-free Ba(Fe(1-x)Co(x))2As2 single crystals. The strong enhancement of the Raman response at low temperatures unveils an underlying charge nematic state that extends to superconducting compositions and which has hitherto remained unnoticed. Comparison between the extracted charge nematic susceptibility and the elastic modulus allows us to disentangle the charge contribution to the nematic instability, and to show that charge nematic fluctuations are weakly coupled to the lattice.