Universal Scaling Behavior and Superfluidity in High Tc Superconductiv…

High temperature superconductivity is continued to be one of the most challenging subjects in this century. This is due to its scientific importance and ultimate technological breakthrough to be expected. Thus far, numerous experimental observations have been made resulting in greater understanding of the physical properties of the low dimensional (2-D) strongly correlated electron systems (cuprate oxides materials) in both the charge (optical conductivity) and spin dynamics (inelastic neutron scattering), not to speak of the electronic structure (ARPES) and the superfluid weight (“Uemura plot”). Electron is simply the object composed of both the charge and the spin. One among the most important observations is the phase diagram in which both the spin and charge degrees of freedom is clearly manifested. They are characterized by the spin gap phase and the superconducting phase respectively. Following a brief review of the experimental observations mentioned above, here we will first present our successful theoretical findings of physical properties of electronic structures, superfluid weight, and both the spin and charge dynamics, which are in complete agreement with observations. Based on our findings on both the charge and spin dynamics, we will sharply focus on the important subject of how the universal scaling behaviors in both the spin and charge degrees of freedom arise. Finally, in connection with the predicted universality of scaling behaviors and the reproduced superfluid weight, we highlight the importance of coupling between the two degrees of freedom in understanding high temperarure superconductivity