Infrared Hall Effect in the electron-doped high Tc cuprate   Pr(2-x)Ce(x)CuO(4)
  The electron-doped cuprate Pr(2-x)Ce(x)CuO(4) is investigated using infrared magneto-optical measurements. The optical Hall conductivity sigma_{xy} shows a strong doping, frequency and temperature dependence consistent with the presence of a temperature and doping-dependent coherent backscattering amplitude which doubles the electronic unit cell. The data suggest that the coherent backscattering vanishes at a quantum critical point inside the superconducting dome and is associated with the commensurate antiferromagnetic order observed by other workers. Using a spectral weight analysis we have further investigated the Fermi-liquid like behavior of the overdoped sample. The observed Hall-conductance spectral weight is about 10 times less than that predicted by band theory, raising the fundamental question concerning the effect of Mott and antiferromagnetic correlations on the Hall conductance of strongly correlated materials. 
A. Zimmers, L. Shi, D. C. Schmadel, W. M. Fisher, R. L. Greene, H. D.   Drew, M. Houseknecht, G. Acbas, M.-H. Kim, M.-H. Yan...