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

Raman spectra of underdoped cuprate superconductors have been studied fur different polarizations and temperatures. Strong anisotropies show up in both the normal and superconducting state. In the normal state below T* approximate 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 excitations are found only at B-2g symmetry and suggest d(x)2(-y)2 pairing with an amplitude Delta(o) of 8kT(c), similar to all other doping levels.lC. Raman spectroscopy, cuprate superconductors. pseudogap, superconducting gap, gap symmetry.