Separation of Quasiparticle and Phononic Heat Currents in YBCO

TL;DR

This study separates quasiparticle and phononic heat currents in YBCO using high magnetic field thermal conductivity measurements, revealing distinct relaxation times and a maximum in quasiparticle conductivity below the superconducting transition.

Contribution

It introduces a method to distinguish quasiparticle from phononic heat transport in YBCO and uncovers different relaxation behaviors below T_c.

Findings

Quasiparticle thermal conductivity peaks below T_c.

Distinct transport and Hall relaxation times below T_c.

Quasiparticle relaxation time is strongly enhanced below T_c.

Abstract

Measurements of the transverse (k_{xy}) and longitudinal (k_{xx}) thermal conductivity in high magnetic fields are used to separate the quasiparticle thermal conductivity (k_{xx}^{el}) of the CuO_2-planes from the phononic thermal conductivity in YBa_2Cu_3O_{7-\delta}. k_{xx}^{el} is found to display a pronounced maximum below T_c. Our data analysis reveals distinct transport (\tau) and Hall (\tau_H) relaxation times below T_c: Whereas \tau is strongly enhanced, \tau_H follows the same temperature dependence as above T_c.