Scientists Find Clue to High-Temperature Superconductivity in Quantum Materials

Scientists have recently discovered the underlying hidden magnetic order in the pseudogap phase of a quantum material. The peculiar phase exists immediately above the superconducting transition. The research team employed an ultracold-atom simulator. They were able to detect a hidden antiferromagnetic order even when the material lacked electrons. This is referred to as doping. This is a crucial phase in designing a novel superconductor at a higher temperature. The findings offer fresh insights into a long-standing problem related to superconductivity.

Ultracold atoms reveal hidden magnetism

According to the reports, to explore the nature of the pseudogap, the researchers employed a cold-atom simulator called the Fermi-Hubbard model. Lithium atoms were chilled to within a few degrees of absolute zero and placed in a lattice created by a laser, which simulated the behaviour of electrons in solids. The quantum gas microscope captured more than 35,000 images of the individual atoms to measure the orientation of their spins. Results indicated the existence of one common pattern of correlations among the spins as the lattice cooled, which is related to a characteristic temperature at which the pseudogap occurs, and found it to be the point at which the hidden antiferromagnetic order develops.

Spin ice and magnetic monopoles

These discoveries are reminiscent of strange occurrences found in ‘spin ice' magnets. The basic structural units of spin ice crystals are frustrated tetrahedrons of magnetic atoms that do not form a traditional order. It has been observed that the reverse process of a spin creates a pair of defects that represent the south and north poles of a magnet – ‘monopoles' of the material. These have actually been observed in neutron scattering experiments.