Catenaa, Monday, December 29, 2025- Researchers have identified a new type of superconductor in platinum bismuth two that breaks established rules of electron behavior and naturally hosts Majorana particles with promise for quantum computing.
The material, known as PtBi2, shows superconductivity only on its top and bottom surfaces while its interior remains a normal metal, according to a study by scientists at IFW Dresden and ct.qmat. Electrons on these surfaces pair and move without resistance at low temperatures, while bulk electrons do not.
This surface-only behavior stems from a topological property that locks electrons to the crystal’s outer layers regardless of thickness. When the crystal is cut, new surfaces immediately develop the same electronic states, preserving superconductivity at the boundaries.
High resolution measurements revealed an even rarer effect. Not all surface electrons join the superconducting state. Electrons traveling in six evenly spaced directions remain unpaired, forming a sixfold symmetric pattern never observed in other superconductors. Conventional materials show no directional limits, while some unconventional types display fourfold symmetry.
Because superconductivity arises from protected surface states, PtBi2 qualifies as an intrinsic topological superconductor. Only a small number of candidates exist, and most lack consistent experimental confirmation, placing PtBi2 among the strongest examples so far.
The study also showed that the edges surrounding the superconducting surfaces trap Majorana particles. These quasiparticles appear automatically due to the material’s topology and can form along natural or engineered step edges.
Majorana particles are central to fault resistant quantum computing since they store information in a way that reduces errors. Researchers say adjusting thickness or applying magnetic fields could allow control over their position, opening a path toward future quantum devices built from a single crystalline material.
