Kinetics of stripes and energy pseudogap in high-temperature superconductors: Coherent nonlinear spectroscopy of phase transition in Y-Ba-Cu-O

摘要

To interpret the data of transient nonlinear spectroscopy of cooper-oxide high-temperature superconductors (HTSCs), a phenomenological model, describing "magneto-dipole" self-organization of charge carriers (holes) in HTSC CuO2 planes and kinetics of the corresponding phase transition, has been developed. It has been shown that, for the exchange energy similar to100 meV and doping level similar to 0.1 hole/cell, the temperature T decrease below the critical point T* similar to 150 K leads to formation of a spatially non-uniform distribution of the holes (the "stripe-structure") and to appearance of corresponding energy gap in the electronic structure. Calculated steady-state dependencies of T* on and of the gap width on T agree with known experimental data. The predicted phase transition kinetics depends on the initial temperature T. When T* < T < T-m approximate to (1.4-1.5)T*, the stripe-structure decay is rather slow (with time similar to10(-9) s and more) two-stage process. During the first stage, a large-scale (with size similar to4-6 cells) fluctuation of an average dipole moment is formed and, only after that, the spatial region, entrained in the fluctuation, broadens due to propagation of the phase switching wave. [References: 37]