Behavior of anisotropic superconductors under uniaxial stress

We investigate theoretically the behavior of anisotropic superconductors under uniaxial stress using the Landau expansion for the free energy. In the cases where the solution of the linearized gap equation belongs to a degenerate representation, there can be a linear coupling to the applied stress leading to a splitting of the transition from a normal to a superconducting state into two (or in some cases even three) second-order transitions. A complete analysis is presented of the resulting phase diagrams. The experimental observation of such splitting would give much information about the symmetry of the superconducting order parameter of the system.