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arXiv · 1911.08733

Scattering rate collapse driven by a van Hove singularity in the Dirac semi-metal PdTe$_{2}$

Erik van Heumen·Maarten Berben·Linda Neubrand·Yingkai Huang
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Abstract

We present optical measurements of the transition metal dichalcogenide PdTe$_{2}$. The reflectivity displays an unusual temperature and energy dependence in the far-infrared, which we show can only be explained by a collapse of the scattering rate at low temperature, resulting from the vicinity of a van Hove singularity near the Fermi energy. An analysis of the optical conductivity suggests that below 150 K a reduction in the available phase space for scattering takes place, resulting in long-lived quasiparticle excitations. We suggest that this reduction in phase space provides experimental evidence for a van Hove singularity close to the Fermi level. Our data furthermore indicates a very weak electron-phonon coupling. Combined this suggests that the superconducting transition temperature is set by the density of states associated with the van Hove singularity.

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Erik van Heumen, Maarten Berben, Linda Neubrand, Yingkai Huang. 2019-11-20. Scattering rate collapse driven by a van Hove singularity in the Dirac semi-metal PdTe$_{2}$. https://doi.org/10.1103/physrevmaterials.3.114202

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