Pseudogap state of novel superconductors: Energy scales and structural and diamagnetic transitions

High T-c cuprates are characterized by three characteristic energy scales: T-c, T-c*, and T*. The lowest scale, T-c, corresponds to the usual transition to the dissipationless state (R = 0) with a macroscopic phase coherence. The higher energy scale, T-c*, describes the diamagnetic transition. The region T-c* > T> T-c is characterized by the presence of superconducting regions embedded in a normal metallic matrix. The highest energy scale (T*) corresponds to the formation of the structure, phase separation, and to the opening of the CDW gap.