Researchers at IFW Dresden and the Cluster of Excellence ct.qmat announced on November 19 that they had identified a new form of superconductivity in the crystalline material PtBi\u2082. This form displayed a topological behavior and an electron-pairing pattern that had never been seen before.<\/p>\n
The findings of this experiment promise a route to generating stable Majorana particles, regarded as the building blocks of future quantum technologies. The new material platform is also key for tackling fault-tolerant quantum computing.<\/p>\n
PtBi\u2082 is intrinsic, with no complex engineering or exotic conditions necessary. This condition opens pathways to control Majoranas, engineer custom qubit architectures, and build more stable quantum devices.<\/p>\n
The new six-fold symmetry<\/p>\n
Most superconductors<\/a> allow electron pairing in all directions, forming a smooth, symmetrical superconducting state. Even in high-temperature cuprate superconductors, the pairing exhibits a four-fold symmetry.<\/p>\n But, PtBi\u2082 is the first of its kind to show a six-fold restricted pairing, a feature tied to the crystal\u2019s underlying three-fold symmetry.<\/p>\n \u201cWe have never seen this before. Not only is PtBi\u2082 a topological superconductor, but the electron pairing that drives this superconductivity is different from all other superconductors we know of,\u201d said Dr. Sergey Borisenko, a researcher on the experiment.<\/p>\n \u201cWe don\u2019t yet understand how this pairing comes about,\u201d he continued.<\/p>\n Automatic formation of Majorana particles<\/p>\n The researchers confirmed that the superconducting state in PtBi\u2082 naturally produces Majorana particles. These particles are elusive, long-hypothesized quasiparticles that behave like \u201csplit electrons\u201d and are immune to many forms of quantum noise.<\/p>\n Theoretical work led by Prof. Jerone van den Brink shows that these Majorana modes are confined to the material\u2019s edges. Intriguingly, by cutting the crystal or by engineering step edges, researchers can generate as many edge-bound Majoranas as needed.<\/p>\n Dissecting PtBi\u2082\u2019s unusual behavior<\/p>\n To help explain the finding, the researchers break PtBi\u2082\u2019s unusual behavior into four steps. First, topological surface states force electrons to live only on the crystal\u2019s outer layers; the states remain intact even if the material is cut.<\/p>\n