Researchers at the University of Basel have created an ultrathin semiconductor with superconducting contacts for the first time. These ultra-thin materials could open up new possibilities for electronic and optical applications. They are expected to be combined with superconductors to create new quantum phenomena.
Semiconductors play an important role in electronics and our daily lives, whether in smartphones, televisions, or building technology. Contrary to metals, you can adjust the electrical conductivity of semiconductors by applying a voltage to turn on or off the current flow.
Researchers are developing new components of one layer (monolayer) of semiconducting materials to improve future electronics and quantum technology applications. Monolayers are a common feature of semiconducting materials that naturally occur. These monolayers can be stacked to create a three-dimensional crystal. Researchers can use these monolayers to make electronic components in the laboratory.
The new properties and phenomena
These ultrathin semiconductors promise unique characteristics that would otherwise be very difficult to control—for example, using an electric field to alter the magnetic moments of electrons. These semiconducting monolayers may also be used for quantum technology because they contain complex quantum mechanical phenomena.
Researchers worldwide are studying how thin semiconductors can be stacked to create new synthetic materials called van der Waals heterostructures. They haven’t been able to combine such a monolayer and superconducting contacts, which would allow them to explore the unique properties of these new materials.
Contacts for superconducting
A team of physicists led by Dr. Andreas Baumgartner at the Swiss Nanoscience Institute and the Department of Physics of the University of Basel has fitted a monolayer of semiconductor molybdenum dioxide with superconducting contact for the first-ever time. (see box)
This combination of superconductors and semiconductors is fascinating because experts expect these components to display new properties and physical phenomena. Baumgartner, the project manager, explained that superconductor electrons are organized in pairs like dance partners. This leads to strange and beautiful results, such as an electrical current flowing without resistance. “In semiconductor molybdenum disulfide, however, the electrons dance differently. They perform a bizarre solo routine that also includes their magnetic moments. We would love to discover which exotic dances the electrons can agree on if we combine these two materials.”
Useful for platform use
The effects of the superconductor are evident in the electrical measurements taken at low temperatures (-273.15degC), which is required for superconductivity. Single electrons are not allowed at specific energies. The researchers also found evidence of strong coupling between the superconductor and semiconductor layer.
“Strong coupling is an important element in the exciting new physical phenomena we expect to see within such van der Waals heterostructures but were unable to demonstrate,” Mehdi Ramezani was the study’s lead author.
Baumgartner says, “And, of course,” he continues, “And, of course,” we continue to hope for new applications in quantum technology and electronics.” The vertical contacts we have developed for semiconductor layers can be applied to many other semiconductors. He says that hybrid monolayer semiconductor components can be made using our measurements.
