Title: Electron-Phonon Interaction in Ternary Rare-Earth Copper Antimonides LaCuSb2 and La(Cu0.8Ag0.2)Sb2 probed by Yanson Point-Contact Spectroscopy,
Abstract: Investigation of the electron-phonon interaction (EPI) in LaCuSb2 and
La(Cu0.8Ag0.2)Sb2 compounds by Yanson point-contact spectroscopy (PCS) has been
carried out. Point-contact spectra display a pronounced broad maximum in the
range of 10÷20 mV caused by EPI. Variation of the position of this maximum
is likely connected with anisotropic phonon spectrum in these layered
compounds. The absence of phonon features after the main maximum allows the
assessment of the Debye energy of about 40 meV. The EPI constant for the
LaCuSb2 compound was estimated to be {\lambda}=0.2+/-0.03. A zero-bias minimum
in differential resistance for the latter compound is observed for some point
contacts, which vanishes at about 6 K, pointing to the formation of
superconducting phase under point contact, while superconducting critical
temperature of the bulk sample is only 1K.