Pseudogap temperature from quasiparticle Nernst effect in La-based cuprates

We compare the Nernst effect in stripe ordered Eu-doped La$_{2-x}$Sr$_x$CuO$_4$ (Eu-LSCO) and similarly hole-doped LSCO. We show that at high temperatures they have essentially the same temperature dependence, showing an upturn and sign change starting at a temperature $T_\nu$. Relating $T_\nu$ to the pseudogap temperature $T^\star$, we present a general phase diagram for LSCO showing that $T^\star$ decreases as the doping increases until it is driven to zero within the superconducting dome. We compare the phase diagram and the $T^\star$ line to the similar ones of YBa$_2$Cu$_3$O$_y$ shown in a recent study [1]. \\ \\ {[1]} R. Daou et al., arXiv:0909.4430