Electron–quasiparticle interaction in DyNi 2B 2C measured by point-contact spectroscopy

Abstract

The electron–quasiparticle interaction (EQI) spectral function has been measured for 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∼5 meV. It becomes measurable at T m*≃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 HoNi 2B 2C suggests that a similar peak also exists for this compound. The magnitude of the point-contact EQI parameter λ PC for DyNi 2B 2C is estimated.