Universal intrinsic scale of the hole concentration in high-T-c cuprates

Article

关键词: OXYGEN-DEFICIENT YBA2CU3OX;    PSEUDO SPIN-GAP;    THERMOELECTRIC-POWER;    NORMAL-STATE;    TRANSPORT-PROPERTIES;    MAGNETIC-PROPERTIES;    TRANSITION-TEMPERATURE;    CARRIER DISTRIBUTION;    SUPERCONDUCTORS;    LA2-XSRXCUO4;   

DOI  :  10.1103/PhysRevB.70.214517

来源: SCIE

【 摘 要 】

We have measured thermoelectric power (TEP) as a function of hole concentration per CuO2 layer P-pl in Y1-xCaxBa2Cu3O6 (P-pl=x/2) with no oxygen in the Cu-O chain layer. The room-temperature TEP as a function of P-pl, S-290(P-pl), of Y1-xCaxBa2Cu3O6 behaves identically to that of La2-zSrzCuO4 (P-pl=z). We argue that S-290(P-pl) represents a measure of the intrinsic equilibrium electronic states of doped holes and, therefore, can be used as a common scale for the carrier concentrations of layered cuprates. We shows that the P-pl determined by this new universal scale is consistent with both hole concentration microscopically determined by NQR and the hole concentration macroscopically determined by the formal valency of Cu. We find two characteristic scaling temperatures, T-S(*) and T-S2(*), in the TEP versus temperature curves that change systematically with doping. Based on the universal scale, we uncover a universal phase diagram in which almost all the experimentally determined pseudogap temperatures as a function of P-pl fall on two common curves; lower pseudogap temperature defined by the T-S(*) versus P-pl curve and upper pseudogap temperature defined by the T-S2(*) versus P-pl curve. We find that while pseudogaps are intrinsic properties of doped holes of a single CuO2 layer for all high-T-c cuprates, T-c depends on the number of layers, therefore, the inter layer coupling, in each individual system.

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