Pseudogap State of Underdoped Cuprate Hts as a Display of The Jahn–Teller Pseudoeffect

Abstract

For underdoped quasi-two dimensional cuprate antiferromagnets within the framework of the two-component model of charge carriers (holes and Zhang–Rice polarons) it is considered two near-degenerate states of hole molecular orbitals of one-site cluster Cu2+O4 2− and two-site cluster Cu2+O4 2−+Cu2+O4 2 in CuO2 planes. It is shown that the vibronic mixing of these near-degenerate states with near energies separated by the energy barrier $$\Delta \varepsilon$$ , leads to transition of the system to the pseudogap state with new quasilocal and local states of charge carriers. The supposition that the pseudogap state is a consequence of the Jahn–Teller pseudoeffect and that barrier $$\Delta \varepsilon$$ is stipulated by magnetic interaction is discussed.