An Observation of Quantized Series of Step or Clew Temperaturesin Superconductive-Conjugate Photoconductivity of Cu2O

Abstract

Details of the temperature dependences of transient photoconductivity Q ( T , λ) with that of Hall mobility µ H ( T ) of photoexcited carriers in Cu 2 O at low power level of λ ex =570-735 nm have been reexamined over a wide temperature range between 4.2 and 300 K in order to clarify the natures of “supercondcutive-conjugate photoconductivity”. Selective optical excitation at low levels of λ ex =570-750 nm creates either a free electron and a positive hole or mainly free holes in Cu 2 O. By carefully analyzing these data, we have recognized for the first time a novel quantized series of “ Step Temperatures T pS ” in Q ( T , λ) with “ Clew Temperatures T pC ”, in the photoexcited holes density n p ( T , λ) in Cu 2 O as T decreases. A series of the values of T pS or T pC is possibly ruled by a type of condensation of valence electrons and free photocarriers into new states mediated via surrounding intraband CT-excitons of Cu 2 O. Here, we propose a new concept of “ the excitonic isomer shift of superconduct...