Pseudogap and superconducting gap in the electronic Raman spectra of underdoped cuprates

Raman spectra of underdoped cuprate superconductors have been studied fur d ifferent polarizations and temperatures. Strong anisotropies show up in bot h the normal and superconducting state. In the normal state below T* approx imate to 200K, a pseudogap Delta* is found near(pi,0) with an energy scale close to that of the magnetic exchange interaction J. Superconducting gap e xcitations are found only at B-2g symmetry and suggest d(x)2(-y)2 pairing w ith an amplitude Delta(o) of 8kT(c), similar to all other doping levels.lC. Raman spectroscopy, cuprate superconductors. pseudogap, superconducting ga p, gap symmetry.