Unified electronic phase diagram for hole-doped high-T_c cuprates

Copyright (2008) by the American Physical Society publisherWe have analyzed various characteristic temperatures and energies of hole-doped high-T_c cuprates as a function of a dimensionless hole-doping concentration (p_u). Entirely based on the experimental grounds, we construct a unified electronic phase diagram (UEPD), where three characteristic temperatures (T^*'s) and their corresponding energies (E^*'s) converge as p_u increases in the underdoped regime. T^*'s and E^*'s merge together with the T_c curve and 3.5k_BT_c curve at p_u~1.1 in the overdoped regime, respectively. They finally go to zero at p_u~1.3. The UEPD follows an asymmetric half-dome-shaped T_c curve, in which T_c appears at p_u~0.4, reaches a maximum at p_u~1, and rapidly goes to zero at p_u~1.3. The asymmetric half-dome-shaped T_c curve is at odds with the well-known symmetric superconducting dome for La_Sr_xCuO_4 (SrD-La214), in which two characteristic temperatures and energies converge as p_u increases and merge together at p_u~1.6, where T_c goes to zero. The UEPD clearly shows that pseudogap phase precedes and coexists with high temperature superconductivity in the underdoped and overdoped regimes, respectively. It is also clearly seen that the upper limit of high-T_c cuprate physics ends at a hole concentration that equals to 1.3 times the optimal doping concentration for almost all high-T_c cuprate materials and 1.6 times the optimal doping concentration for the SrD-La214. Our analysis strongly suggests that pseudogap is a precursor of high-T_c superconductivity, the observed quantum critical point inside the superconducting dome may be related to the end point of UEPD, and the normal state of the underdoped and overdoped high temperature superconductors cannot be regarded as a conventional Fermi liquid phase.©2008 The American Physical Societ