PHASE TRANSITION IN SUPERCONDUCTORS

Abstract

Phenomena of phase transition are a possible consequence of molecular interaction as in ordinary matter and superfluid systems, such as liquid, or electrons and nucleons interaction. These interactions are believed to be the cause of superconductivity of different types of materials and the Superfluidity of nuclear matter. It is also well known that the interaction between the electrons in the superconducting state may be different for different materials. Thus, for any high superconductor a possible type of electron-electron interaction may be used as a perturbation and the theory of second quantization may be used to study the possible phase transition in that material. According to the theory of second quantization, if a perturbation commutes with the rest of the Hamiltonian, it leads to a phase transition. Using theory of second quantization, a theoretical calculation has been performed to investigate the commutability in electron-phonon interaction, simultaneous existence of electron phonon and coulomb interaction and exotic pairing as a characteristic of phase transition in a superconductor. Calculations show that the three interaction commutes with unperturbed Hamiltonian and may lead to a phase transition.