Seminários

In this talk I introduce the concept of superconducting fitness, which allows us to make statements analogous to Anderson's theorems concerning the stability of different superconducting states. This concept can be applied to complex materials with several orbital, layer, sublattice or valley degrees of freedom. The superconducting fitness functions FA(k) and FC(k) give a direct measure of the robustness of the weak coupling instability and of the presence of detrimental terms in the normal state Hamiltonian, respectively. These two functions can be employed as a guide to engineer normal state Hamiltonians in order to favour or suppress superconducting order parameters with different symmetries and topological properties. To illustrate the applicability and power of this concept, I take you over the following examples: the putative chiral p-wave superconductor Sr2RuO4, the non-centrosymmetric heavy fermion CePt3Si, the hole doped iron pnictide KFe2As2 and the doped topological insulator CuxBi2Se3.