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

TL;DR

This study reveals a fundamental link between the Nernst effect and nodal quasiparticle transport in the pseudogap phase of underdoped cuprates, supported by measurements on La2-xSrxCuO4 crystals.

Contribution

It demonstrates the intrinsic relation between the Nernst signal and quasiparticle transport, and introduces a phase diagram indicating a second energy scale in the pseudogap region.

Findings

Nernst signal boundary Tn coincides with resistivity T_R.

Resistivity exhibits a T^2 dependence below T_R.

A phase diagram with a second pseudogap energy scale is proposed.

Abstract

In-plane Nernst signal and resistivity have been measured for three $La_{2-x}Sr_xCuO_4$ 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., $\rho=\rho_0+aT^2$ 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 $T^*$ is presented, which suggests a second energy scale in the pseudogap region.