Electron–phonon coupling in superconducting 1T-PdTe2

• Main Authors: Gloria Anemone, Pablo Casado Aguilar, Manuela Garnica, Fabian Calleja, Amjad Al Taleb, Chia-Nung Kuo, Chin Shan Lue, Antonio Politano, Amadeo L. Vázquez de Parga, Giorgio Benedek, Daniel Farías, Rodolfo Miranda
• Format: Article
• Language: English
• Published: Nature Publishing Group 2021-02-01
• Series: npj 2D Materials and Applications
• Online Access: https://doi.org/10.1038/s41699-021-00204-5

Abstract We have determined the electron–phonon interaction in type II Dirac semimetallic 1T-PdTe2 by means of helium atom scattering. While 1T-PdTe2 is isostructural with 1T-PtTe2, only the former is superconductor. The difference can be traced to the substantially larger value of the electron–phonon coupling in 1T-PdTe2, λ = 0.58, obtained from the Debye-Waller attenuation of the He specular peak. With this value and the surface Debye temperature, ΘD = 106.2 K, we have figured out the superconducting critical temperature, T c = 1.83 K given by the BCS theory, which is in good agreement with T c = (1.95 ± 0.03) K obtained with low-temperature scanning tunneling microscopy. The value of the effective mass related to ΘD indicates that the large electron–phonon coupling in 1T-PdTe2 is due to coupling, not only with the zone-center optical mode O2 at 9.2 meV, as proposed in a recent theoretical study, but also with the zone-boundary acoustic mode LA. Our results suggest that the topological states of a Dirac cone play a negligible role on the onset of superconductivity.