Two-dimensional (2D) materials, such as graphene or transition metal dichalcogenides, can sometimes be assembled into bilayers with a twist between individual layers. In recent years, many researchers have been investigating the properties of these twisted double-layer structures and their potential advantages for fabricating electronic devices.
A research group at the University of British Columbia in Vancouver recently carried out a study exploring the properties of twisted double-layer copper oxides. In their paper, published in Nature Physics, they predict that structures composed of two monolayer-thin d-wave superconductors will exhibit high-temperature topological superconductivity.
"Twisted bilayer graphene has been a big research topic over the past couple of years, and we were thinking about other 2D materials where twist-angle engineering could be applied," Marcel Franz, one of the researchers who carried out the study, told Phys.org. "The goal of our work, however, was to uncover some new physics, not just repeat what others have done in the context of graphene. After several false starts, we zeroed in on cuprate superconductors, which share some similarities with graphene, such as 2D basic structure and low-energy Dirac excitations, but are also in many aspects very different materials."
The most notable difference between graphene and cuprate-based superconductors is that they conduct electricity with no resistance at high temperatures. This characteristic could make them arguably more suitable for fabricating topological superconductors.
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