The two researchers have joined forces in the search for suitable materials and possible practical applications of this so-called non-linear Hall effect. While Ortix is a theoretical physicist, Makarov brings in the experimental know-how – and the connection to other institutes at the HZDR, which are significantly involved in the work with their expertise. “We got together with colleagues from the ELBE Center for High Power Radiation Sources, the High Magnetic Field Laboratory and the Institute for Resource Ecology. The common goal: to identify a suitable material with which this quantum effect can appear in a controlled manner at room temperature and which is also easy to handle and non-toxic,” says Makarov, describing the starting point of the joint work.

Familiar Material, New Properties

In the elemental material bismuth, the team has found a candidate that exhibits these properties. Bismuth is known for its strong classical Hall effect which is present in the bulk of the material. The researchers discovered that on surfaces instead, quantum effects dominate and govern the current flow even at room temperature.

A major advantage of the approach is that the researchers can apply their thin films with quantum properties to a variety of substrates for electronics like silicon wafers and even plastic. The team achieves the control of the effect through sophisticated micro-fabrication: they can directly influence the currents via the geometry of the channels on chip.

New Quantum Materials With Technological Relevance

Other teams had already created a number of materials that exhibit the non-linear Hall effect, but they do not combine all the desirable properties. Graphene, for example, is environmentally safe and its non-linear Hall effect can be controlled well, but only at temperatures below around -70 degrees SciTechDaily