Possible Explanation of the Pseudogap in High-Temperature Cuprates

A concept describing the origin and some properties of the ``pseudogap phase'' of high-${T}_{c}$ superconducting cuprates is proposed based on the author's idea about resonant tunneling connection between the ${\mathrm{CuO}}_{2}$ layers. The superconducting critical temperature in this picture is defined at low doping by establishment of a three-dimensional phase correlation between the layers, and at high doping by destruction of a d-wave superconductivity by disorder. The result is a nonmonotonic behavior of ${T}_{c}$ with doping. The pseudogap phase is analyzed qualitatively on the basis of the recently discovered existence of vortices in this phase and one-dimensional fluctuations due to extended saddle points (``hot spots'').