New superconductor shows quantum edge states tied to Majorana physics

Researchers at IFW Dresden and the Cluster of Excellence ct.qmat have discovered a novel form of superconductivity in the crystalline material PtBi₂, characterized by a unique six-fold electron pairing symmetry linked to the crystal’s inherent three-fold symmetry. This topological superconductivity differs fundamentally from previously known types, and notably, PtBi₂ is an intrinsic superconductor that does not require complex engineering or exotic conditions. The material naturally hosts Majorana particles—quasiparticles theorized to behave like “split electrons” and resistant to quantum noise—confined to its edges, which can be generated in controllable numbers by cutting or engineering step edges in the crystal. The researchers explain PtBi₂’s behavior through a four-step process: topological surface states localize electrons on the crystal’s outer layers; these surface electrons become superconducting at low temperatures while the interior remains metallic, creating a “superconductor sandwich”; the electron pairing on the surface exhibits an unprecedented six-fold symmetry with six directions where