Anomalous phonon peak in the superconducting state of (formula presented)

Abstract

An anomalous phonon peak that appears only in the superconducting state has been reported for nonmagnetic intermetallic superconductor (formula presented) (formula presented) Lu). In the present paper, we shall demonstrate that another rare-earth borocarbide (formula presented) seems to show similar phonon anomalies. A spectral weight transfer from the above-lying TA phonon mode to the aforementioned peak was rather small, but it is consistent with the theoretical prediction for the system with smaller (formula presented) ratio. Combining the present results with those observed in the other borocarbide systems, we suggest that such a phonon anomaly might be a common phenomenon for superconductors with a strong nesting feature of the Fermi surface. © 2002 The American Physical Society.