Qualitative explanation of the temperature behaviors of the transport properties and magnetic susceptibility of high-temperature superconductors in the normal state

TL;DR

This paper proposes a structural model for high-temperature superconductors that explains their temperature-dependent transport properties and magnetic susceptibility, highlighting the roles of different carriers and doping levels.

Contribution

It introduces a new model based on alternating layers to explain anisotropies and temperature behaviors in high-Tc superconductors, including doping effects and Fermi liquid transition.

Findings

The model accurately predicts resistivity and Hall angle temperature dependence.

It clarifies the physical meaning of hole density and doping levels.

Explains the transition to Fermi liquid behavior in overdoped regions.

Abstract

A model based on the alternating structure of the imbedded conduction layers (the Cu-O2 planes) with the charge-transfer-insulator (CTI) layers is proposed. There are three kinds of carriers, each with a different behavior: conduction-like holes in the Cu-O2 layers and electrons and normal holes in the CTI matrix between the Cu-O2 layers. This structure explains the strong anisotropies. The relationship is obtained between the concentration nq of conduction-like holes in the Cu-O2 layers and the temperature T. The anomalous temperature behavior of the resistivity as well as the Hall constant also follows. We give the hole density in ab plane a definite physical meaning, and also define explicitly optimal doping, overdoping and underdoping. Our model gives the correct temperature dependence of the resistivity and the hole constant on optimal doping, overdoping and underdoping, and it predicts the temperature behavior of the cotangent of the Hall angle quite well. Based on this model, we can also understand that the HiTc materials become "Fermi Liquids" in the extremely overdoped region, and the dR/dT becomes negative below some temperature T<1.211T0 in the underdoped case. Based on this model, the thermal behaviors of the magnetic susceptibility in different doping can also be easily explained. The resistivity along c-axis is discussed.