INSTABILITIES TOWARDS SUPERCONDUCTIVITY AND INCOMMENSURATE BOND-ORDERWAVES IN THE T-J MODEL

Using a 1/N expansion for X-operators and enforcing the constraints lo cally the kernel of the superconducting gap equation has been calculat ed for the t-J model. Spin-flip and, to a lesser degree, charge and in stantaneous contributions to the kernel cause a strong instability for d-wave superconductivity with a T-c of order 0.01t, where t is the ne arest-neighbor hopping integral. In the underdoped case this instabili ty competes with another instability towards an incommensurate bond-or der wave.