Hunting Weyl Fermions in microstructured topological semi-metals

Graphene’s remarkable electronic properties arise from its peculiar electronic structure that is characterized by a linear dispersion around a band crossing point, forming the famous two-dimensional “Dirac cones”. In recent years, three-dimensional semi-metals have been discovered with 3D linear dispersions, forming the materials class of Weyl- and Dirac-semi-metals. Similarly, remarkable electronic properties such as the appearance of well-defined electron chirality and novel mechanisms leading to large electronic mobilities have been predicted. When conductors hosting electrons with unusual properties are discovered, it is natural to ask if they can be used for new types of electronic applications.

I will discuss the prospects and recent advances in topological electronics, which directly exploit the topological character of the electrons in these materials. In particular, the cyclical conversion of electron chirality induced by strong magnetic fields is evidenced by an oscillatory magnetoresistance akin to Shubnikov-de Haas oscillations. I will present design concepts for topological electronics elements such as the topological voltage inverter, which are part of the ongoing research in our group.
P.J.W.M et al., Nature 535, 266-270 (2016)

Bio:
Dr. Philip Moll received his M.Sc. and PhD at ETH Zurich in 2008. His PhD work on the identification of the technologically relevant anisotropies of resistivity, flux flow and critical currents in iron-based superconductors was awarded the ETH medal and the ABB award of the Swiss Physical Society. A significant part of the thesis concerned the application potential of iron-arsenides in extreme magnetic fields, which he experimentally explored at the US National High Magnetic Field Laboratory in Tallahassee, FL, and Los Alamos, NM. After graduation, he joined the quantum materials laboratory of James Analytis at UC Berkeley, where he worked on microfabrication of Dirac semi-metals towards first prototypes of applications. In 2015, he was awarded an independent Max-Planck-Research-Group, which he established at the MPI for Chemical Physics of Solids in Dresden, Germany. In the interdisciplinary spirit of the institute, his group “microstructured quantum matter” works with chemists, materials scientists and physicists to understand novel electronic materials on the mesoscale and to assess their potential for applications.