Inherent Relation between Nernst Signal and Nodal Quasiparticle Transport in Pseudogap Region of Underdoped High Temperature Superconductors

Abstract

In-plane Nernst signal and resistivity have been measured for three $L{a}_{2-x}S{r}_{x}Cu{O}_4$ single crystals (x=0.09, 0.11 and 0.145) with the magnetic field parallel to c-axis. A quadratic temperature dependence of resistivity, i.e., $\rho ={\rho }_0+a{T}^2$ is observed below a certain temperature $T_R$. It is found that the upper boundary of the Nernst signal $T_n$ coincides with $T_R$, which points to an inherent relation between the anomalous Nernst signal and the nodal quasiparticle transport in the pseudogap region. Finally a phase diagram together with the pseudogap temperature $T^{\ast }$ is presented, which suggests a second energy scale in the pseudogap region.

4 pages, 4 figures