Electron–phonon coupling in superconducting 1T-PdTe2
Gloria Anemone, Pablo Casado Aguilar, Manuela Garnica, F. Calleja, Amjad Al Taleb, Chia-Nung Kuo, C. S. Lue, Antonio Politano, Amadeo L. Vázquez de Parga, G. Benedek, Daniel Farı́as, Rodolfo Miranda
Abstract
Abstract We have determined the electron–phonon interaction in type II Dirac semimetallic 1T-PdTe 2 by means of helium atom scattering. While 1T-PdTe 2 is isostructural with 1T-PtTe 2 , only the former is superconductor. The difference can be traced to the substantially larger value of the electron–phonon coupling in 1T-PdTe 2 , λ = 0.58, obtained from the Debye-Waller attenuation of the He specular peak. With this value and the surface Debye temperature, Θ D = 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 Θ D indicates that the large electron–phonon coupling in 1T-PdTe 2 is due to coupling, not only with the zone-center optical mode O 2 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.