The Origin of an Inflection Point on the Temperature Dependence of the London Penetration Depth in Hole-Doped Cuprate High-Temperature Superconductors

A scenario of the formation of an experimentally observed inflection point on the temperature dependence of the London penetration depth lambda in cuprate high-temperature superconductors (HTSCs) with optimal hole doping is discussed within the spin-polaron concept. It is shown that the reason for the appearance of an inflection point on the 1/lambda(2)(T) dependence is due to the features of the energy spectrum of spin-polaron quasiparticles in the superconducting phase, as well as to the specific temperature dependence of their spectral density.