Seminarium Fizyki Materii Skondensowanej

Recent widespread interest in topological materials intensified studies on various compounds containing heavy elements, like Pb or Bi. This is of course related to the strong spin-orbit coupling (SOC), which should be present in such materials, and should strongly influence their physical properties. Because some of these materials exhibit superconductivity, a natural question arises what is the spin-orbit coupling effect of the electron-phonon interaction and superconductivity of such materials, containing heavy elements?Thanks to the ongoing development of computational techniques, calculations of the electron-phonon interaction function, taking into account the spin-orbit coupling, became available recently. In this work we present several case studies, where the spin-orbit interaction effects on the electronic structure, phonons, and the electron-phonon coupling (EPC) is investigated using density-functional calculations.As the prime example we will shortly discuss the role of spin-orbit interaction in determining the electronic and phononic properties of the elemental Pb and Pb-Bi alloy, which is probably the strongest coupled electron-phonon superconductor. Next we will discuss the case of a type-I superconductor CaBi2 and explain the mechanism behind the almost twice reduction of EPC constant by SOC. As the last example we will study a noncentrosymmetric ThCoC2, where SOC splits the Fermi surface but surprisingly has a little impact on the electron-phonon interaction.