Researchers discovered uranium ditelluride exhibits a rare phenomenon known as re-entrant superconductivity, making it a promising material for use in quantum computers. (Image credit: University of Maryland)
Researchers from the University of Maryland, NIST (National Institute of Standards and Technology), the National MagLab (National High Magnetic Field Laboratory), and the University of Oxford have observed an unusual phenomenon known as re-entrant superconductivity in uranium ditelluride, a now promising material for quantum computers. The researchers nicknamed the effect “Lazarus superconductivity,” which occurs when a superconducting state arises, crumbles, and then reemerges in the material when in the presence of a strong magnetic field.
Uranium ditelluride was once dismissed by physicists for being a lackluster material with no interesting physical properties but has since made a comeback due to its unusual superconductive state. Previous research by the team using uranium ditelluride noted a rare and exotic ground state known as ferromagnetic spin-triplet superconductivity (electron spins with three different orientations), which has a strong resistance to magnetic fields, and thus an excellent choice for building qubits of an efficient quantum computer.
Physics professor Johnpierre Paglione states, “This is indeed a remarkable material, and it’s keeping us very busy. Uranium ditelluride may very well become the ‘textbook’ spin-triplet superconductor that people have been seeking for dozens of years, and it likely has more surprises in store. It could be the next strontium ruthenate—another proposed spin-triplet superconductor that has been studied for more than 25 years.” Superconductivity is a set of physical properties wherein electrical resistance disappears, and magnetic flux fields are expelled in certain materials, allowing electrons to move unrestricted. Copper-based elements (second only to silver), for example, lose 20% power over long distances as the particles bounce around during travel.
Lazarus superconductivity, on the other hand, is strange in its mockup as magnetic fields tend to kill its superconductive state in materials such as copper, unlike uranium ditelluride, which produces Lazarus superconductivity, not once, but twice. The researchers tested the material using super-high magnetic fields up to 65 teslas (30X more potent than an MRI magnet) to crush the material’s superconductivity.
They also experimented with orienting the uranium ditelluride crystals at different angles while pounding it with magnetic fields and found at 16 teslas most tests showed that the magnetic field dissipated, however, at a different angle, the field persisted. At 65 teslas, the magnetic field continued, proving that orienting the uranium ditelluride produced two field-induced superconducting phases in a single compound. The team feels that the material shows every sign of being a topological superconductor and acts as a great component for quantum computers in the future.
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