For more details, read our paper in Optica.

For more details, read our paper in the Journal of Applied Physics.

For more details, read our paper in Nature Nanotechnology.

We show that the doping and temperature evolution of the resistivity can be fully understood from changes in the Drude momentum relaxation rate. At the same time, the carrier density displays a continuous and gradual evolution across the phase diagram.

More can be read in our manuscript in Physical Review B.

See this link for the article.

The program aims to investigate materials with which the researchers want to find novel ways to gain control over their electrical properties.

Next to Van Heumen, also Dr. Anne de Visser from the UvA-Institute of Physics is involved in the consortium that consists of 9 other researchers from in total 6 Dutch Universities. The consortium aims to kickstart a new field of research, with the goal to develop novel materials that change their electrical or magnetic properties strongly under small perturbations such as pressure, temperature or applied electric field. To achieve this goal, the TOPCORE program combines groundbreaking ideas from the mathematical field of topology with experiments and theoretical investigations of recently discovered materials. More information about the open competition can be found on the NWO website.

The program revolves around the spatial symmetries and the understanding of emergent spatial structures in both experimental observations and holographic treatment. Together with Christiana Pantelidou, Alexander Krikun and Milan Allen we have been able to attract funding from ICAM-I2CAM to host this workshop. The workshop details can be found on the Strange metal program website.

PdTe2 has recently attracted much attention for the possible existence of a low temperature, topological superconducting state. In a new publication in Physical Review Materials we report high resolution infrared, optical data as function of temperature. Our high quality reflectivity data allows us to study the optical conductivity of the normal state in detail. We observe a sharp Drude response and several interband transitions that can be associated with the bands forming the Dirac metal phase in this material.

From an analysis of the complex optical conductivity we extract the frequency and temperature dependent scattering rate, 1/τ(ω,Τ).

We find that the scattering rate decreases to a value below our detection limit below 50 K. The paper explains that this points to the presence of a van Hove singularity within 20-30 meV of the Fermi level. This observation has important ramifications for the mechanism of superconductivity in these materials and possibly could be evidence for an important role of the density of states in determining the superconducting properties of transition metal di-chalcogenides.

Scattering rate collapse driven by a van Hove singularity in the Dirac semimetal PdTe2 Erik van Heumen, Maarten Berben, Linda Neubrand, and Yingkai Huang Phys. Rev. Materials 3, 114202 (2019)