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