Effects of doping on thermally excited quasiparticles in the high-$T_c$ superconducting state

TL;DR

This paper investigates how doping affects low-energy quasiparticles in high-temperature superconductors, revealing a doping-dependent density of states and doping-independent renormalization factors, enhancing understanding of superconducting properties.

Contribution

It provides new insights into the doping dependence of quasiparticle density of states and superfluid density renormalization in high-$T_c$ superconductors.

Findings

Quasiparticle density of states scales with doping and temperature.

The linear temperature term of superfluid density is renormalized by interactions.

Renormalization factor times Fermi velocity is doping independent.

Abstract

The physical properties of low energy superconducting quasiparticles in high- $T_c$ superconductors are examined using magnetic penetration depth and specific heat experimental data. We find that the low energy density of states of quasiparticles of La$_{2-x}$Sr$_x$CuO$_4$ scales with $(x-x_c)/T_c$ to the leading order approximation, where $x_c $ is the critical doping concentration below which $T_c=0$. The linear temperature term of the superfluid density is renormalized by quasiparticle interactions and the renormalization factor times the Fermi velocity is found to be doping independent.