# Electron-quasiparticle interaction in $\rm DyNi_2B_2C$ measured by point-contact spectroscopy

## TL;DR

This study measures the electron-quasiparticle interaction spectral function in DyNi2B2C using point-contact spectroscopy, revealing a low-frequency peak linked to electron interactions with crystal-electric-field-phonon excitations, and compares it with similar compounds.

## Contribution

First measurement of the EQI spectral function in DyNi2B2C using PCS, identifying a low-energy peak from electron interactions with coupled excitations.

## Key findings

- Identified a low-frequency peak around 5 meV in the EQI spectrum.
- Peak appears below approximately 15 K and increases with decreasing temperature.
- Estimated the EQI parameter λ_PC for DyNi2B2C.

## Abstract

The electron-quasiparticle interaction (EQI) spectral function has been measured for $\rm DyNi_2B_2C$ in the normal state at low temperatures by means of point-contact spectroscopy (PCS). A low-frequency peak is found around $eV\sim 5\ meV$. It becomes measurable at $T_m^*\simeq 15\ K$ and grows in intensity with constant width as the temperature is lowered. We argue that this peak arises from the strong interaction of conduction electron with coupled crystal-electric-field-phonon excitations whose branches cross at low energy. The comparison with PC spectra for $\rm HoNi_2B_2C$ suggests that a similar peak also exists for this compound. The magnitude of the point-contact EQI parameter $\lambda_{PC}$ for $\rm DyNi_2B_2C$ is estimated. $\copyright$2000 Published by Elsevier Science B.V. All rights reserved.