Paired carrier effective mass isotope effect in the two-band model

By modelling the two-component scenario of high-Tc superconductivity the isotope effect (β) in the supercarrier effective mass is calculated by a two-band scheme with interband pair scattering. The behaviour of Tc, α and β in the underdoped region is illustrated. The repulsive interband interaction contains only a small electron-phonon contribution. The dependence of β (also of Tc, α) on doping is as observed, where β is larger. (orig.)