Pushing transport to the edge: inducing superconductivity in WTe₂

WTe₂ is a promising material to study quantum effects relevant for quantum computing. In WTe₂ the surface and edge states behave differently in transport measurements from its bulk character. This difference is caused by the topological nature of WTe₂ as a type-II Weyl semimetal and a higher-order topological state, which means this transport behaviour is intrinsically embedded in the band structure of WTe₂. The surface and edge states can form an interesting platform to study Majorana-physics particularly when superconductivity is induced in these states.



We measured the electronic transport properties of thin, nanometer sized WTe₂ devices at low temperatures. Superconductivity was successfully induced into the WTe₂ flakes by using superconducting Nb-contacts. While the entire flake exhibited superconducting behavior, the topological nature of WTe₂ is expected to enhance the supercurrent at the edges. By analyzing the field dependence of the critical current, we extract the current distribution within the WTe₂ flake-based Josephson junction. Our measurements on these structures show a clear current enhancement at the edge of the flake compared to the bulk supercurrent. Interestingly, this enhancement is also observed at step edges caused by thickness variations within the flake.