On the dynamic distinguishability of nodal quasi-particles in overdoped cuprates

TL;DR

This paper investigates the dynamic distinguishability of nodal quasi-particles in overdoped cuprates, linking electron-electron collision rates to phase transitions and the emergence of superconductivity.

Contribution

It introduces a novel perspective on how electron interactions lead to dynamic distinguishability, affecting the electronic phase behavior in overdoped cuprates.

Findings

Electron-electron collision rate is unusually large above the doping threshold.

Nodal quasi-particles exhibit a scattering time similar to liquid $^3$He at melting pressure.

Dynamically distinguishable carriers exclude from the Fermi sea, influencing scattering processes.

Abstract

La$_{1.67}$Sr$_{0.33}$CuO$_4$ is not a superconductor and its resistivity follows a purely T$^2$ temperature dependence at very low temperatures. La$_{1.71}$Sr$_{0.29}$CuO$_4$, on the other hand, has a superconducting ground state together with a T-Linear term in its resistivity. The concomitant emergence of these two features below a critical doping is mystifying. Here, I notice that the electron-electron collision rate in the Fermi liquid above the doping threshold is unusually large. The scattering time of nodal quasi-particles expressed in a dimensionless parameter $\zeta$ is very close to what has been found in liquid $^3$He at its melting pressure. In the latter case, fermionic particles become dynamically distinguishable by excess of interaction. Ceasing to be dynamically indistinguishable, nodal electrons will be excluded from the Fermi sea. Such non-degenerate carriers will then scatter the degenerate ones within a phase space growing linearly with temperature.