Energy of plasmon-mediated boson-fermion pair condensate in high temperature superconductors

Abstract

Interaction between particles in condensate state is nontrivial in understanding charge pairing that defines high-temperature superconductivity . A Bose-Einstein Condensate (BEC) of a non-zero-momentum Cooper pair constitutes a composite boson. A two-component electronic BEC - bosons and fermions -harbours some properties that are closely related to those of high temperature superconductors. We demonstrated that quantum coherence of a boson-fermion condensate is controlled by plasmons. A binary electronic system has an associated response function, given by the zero of longitudinal dielectric function. The response function has both long and short-wavelength branches, at least in layered superconductors. Coulomb screening of bosons by the electron cloud, in the long-wavelength branch, drives plasmon mediation in boson-fermion (BF) pairing. This study reveals that: the attractive potential in boson-fermion pair condensate (BFPC) is anisotropic, the magnitude of collective BEC excitations is in the order of an energy gap and that boson-fermion coherence under plasmon-mediation occurs at 10-9 m.