Inhomogeneity of the pseudogap state of a doped layered cuprate antiferromagnet

Abstract

The features of the pseudogap state in doped layered cuprate antiferromagnets and underdoped high-Tc superconductors (HTSCs) are investigated. It is shown that the transition to the pseudogap state is a dimensional crossover from three-dimensional motion to two-dimensional motion of charges in the copper–oxygen planes, which leads to the coexistence of light charge carriers and Jahn–Teller polarons and to the development of strong local correlations, as are characteristic for two-dimensional doped Mott–Hubbard insulators. In a doped antiferromagnet the d-wave pairing of light charge carriers and Jahn–Teller polarons leads to the formation of magnetic and bosonic clusters, i.e., substantial inhomogeneity of the copper–oxygen planes arises. It is found that the change in the properties of a doped layered cuprate antiferromagnetic insulator and in the metallic and superconducting states of an underdoped HTSC with decreasing temperature is due to a repeated dynamic reduction of their dimensionality. A model phase diagram in terms of the temperature and dopant concentration is proposed.