The Condensation Energy and Pseudogap Energy Scale of La2-xSrxCuO4 from the Electronic Specific Heat and Entropy


From the analysis of the electronic specific heat Ces and the entropy Ss of the superconducting phase of nine samples of high temperature superconductor (HTS) La2-xSrxCuO4 (La:214) of Sr doping rates (0.03≤x≤0.24), it is shown that the normal state pseudogap opens abruptly in the weakly overdoped region at the critical doping pcrit (Where x=0.20 and the hole concentration in CuO2 planes is 0.19 holes/CuO2) and increases as Eg(p)~1500(1-p/pcrit.)(K) at lower doping . The condensation energy Ec(0) peaks strongly at the optimal doping dopt (where x=0.17 and the hole concentration in CuO2 planes is 0.16 holes/CuO2), exhibiting strong BSC like superconductivity (Ec(0)/γnTc2~ 0.52 for p>popt) and weak superconductivity below pdopt . It can be concluded that the pseudogap is a property of the normal state NS density of state DOS and is not related to precursor superconducting fluctuations