Ab initio investigation of phonon dispersion and anomalies in palladium

Abstract

In recent years, palladium has proven to be a crucial component for devices ranging from nanotube field effect transistors to advanced hydrogen storage devices. In this work, I examine the phonon dispersion of fcc Pd using first principle calculations based on density functional perturbation theory (DFPT). While several groups in the past have studied the acoustic properties of palladium, this is the first study to reproduce the full phonon dispersion and associated anomaly in the [110]-direction with high accuracy and no adjustable parameters. I will show that the [110] anomaly is a Kohn anomaly due to electron-phonon interactions and that paramagnons play no significant role in the [110] phonon dispersion.