Macroscopic Quantum Tunneling and Quasiparticle Dissipation in d-wave Superconductor Josephson Junctions

TL;DR

This paper investigates macroscopic quantum tunneling in high-temperature superconductor Josephson junctions with d-wave symmetry, revealing how quasiparticle tunneling affects tunneling rates depending on the twist angle.

Contribution

It provides an analytical calculation of the MQT rate in d-wave superconductor Josephson junctions using a microscopic Hamiltonian and functional integral method, highlighting the impact of nodal quasiparticles.

Findings

Zero twist angle shows super-Ohmic dissipation due to nodal quasiparticles.

MQT rate is significantly suppressed at zero twist angle.

Finite twist angles exhibit less dissipation and higher tunneling rates.

Abstract

We examine the macroscopic quantum tunneling (MQT) in high-Tc superconductor Josephson junctions with a d-wave order parameter. Using microscopic Hamiltonian and the functional integral method, we analytically obtain the MQT rate (the inverse lifetime of the metastable state) for the c-axis twist Josephson junctions. In the case of the zero twist angle, the system shows the super-Ohmic dissipation due to the presence of the nodal quasiparticle tunneling. Therefore, the MQT rate is strongly suppressed in compared with the finite twist angle cases.