Relativistic framework for microscopic theories of superconductivity. II. The Pauli equation for superconductors

It is shown that the interplay between relativity and coherence, found in superconductors with heavy elements, leads to a number of interesting and previously unknown effects. In particular, several types of spin-orbit coupling are shown to exist only in superconductors. Explicit expressions describing these effects are derived using a covariant formulation of the theory of superconductivity. It is demonstrated that relativistic effects can become relevant, e.g., in high-temperature and heavy-fermion superconductors, superconducting heterostructures, and rotating superconductors.