Germanene breakthrough shows quantum states can switch on command

Dutch researchers from the University of Twente and Utrecht University have demonstrated for the first time that quantum states in ultra-narrow germanene nanoribbons can be switched on and off using only a local electric field. Germanene, a material similar to graphene but composed of a single layer of germanium atoms arranged in a slightly wavy sheet, exhibits zero-dimensional topological end states when cut into ribbons just a few atoms wide. These topological states are of great interest because they naturally resist noise, a major obstacle in quantum computing, making them promising candidates for more stable qubit components. In their experiments, the team used a scanning tunneling microscope to precisely control the electric field by adjusting the tip-to-surface distance, thereby toggling the presence of these topological end states on command. The switching behavior depended on the ribbon width: in ultra-narrow ribbons, the end states disappeared at higher fields, whereas in wider ribbons, stronger fields activated the states. Theoretical modeling helped explain this geometry-dependent