Effects of gap and band anisotropy on spin susceptibility in the oxide superconductors

We have studied the momentum space anisotropy present in the imaginary part of the spin susceptibility when an extended s-wave component (sx2+y2) is added to the d-wave (dx2-y2) superconducting gap. It is found that as the amount of the extended s-wave component is increased, the two pairs of incommensurate nesting peaks begin to differ increasingly in height and shape. In addition, band structure anisotropy, which in contrast to gap anisotropy would be present even in the normal state, is also discussed. copyright 1996 The American Physical Society