Magnetic-field-dependent quasiparticle energy relaxation in mesoscopic wires

TL;DR

This study investigates how magnetic fields influence quasiparticle energy relaxation in mesoscopic silver wires, revealing sample-dependent effects and aligning with theoretical models involving magnetic impurities and Kondo physics.

Contribution

It provides experimental evidence on magnetic-field effects on quasiparticle distributions, highlighting the role of magnetic impurities and Kondo physics in mesoscopic conductors.

Findings

Magnetic field sharpens energy distributions in one sample.

No magnetic field effect observed in the other sample.

Results agree with models involving magnetic impurities and Kondo physics.

Abstract

In order to find out if magnetic impurities can mediate interactions between quasiparticles in metals, we have measured the effect of a magnetic field B on the energy distribution function f(E) of quasiparticles in two silver wires driven out-of-equilibrium by a bias voltage U. In a sample showing sharp distributions at B=0, no magnetic field effect is found, whereas in the other sample, rounded distributions at low magnetic field get sharper as B is increased, with a characteristic field proportional to U. Comparison is made with recent calculations of the effect of magnetic-impurities-mediated interactions taking into account Kondo physics.