The monolayer of molybdenum disulfide (MoS2) is sandwiched in between 2 protective layers of boron nitride (hBN), with molybdenum rhenium (MoRe) contacts extending through the upper one. A layer of graphene (gate) is utilized for electrical control. Credit: Mehdi Ramezani, Swiss Nanoscience Institute, University of Basel
For the very first time, University of Basel scientists have actually geared up an ultrathin semiconductor with superconducting contacts. These exceptionally thin products with unique electronic and optical residential or commercial properties might lead the way for formerly unimagined applications. Combined with superconductors, they are anticipated to trigger brand-new quantum phenomena and discover usage in quantum innovation.
Whether in smart devices, tvs or constructing innovation, semiconductors play a main function in electronic devices and for that reason in our daily lives. In contrast to metals, it is possible to change their electrical conductivity by using a voltage and for this reason to change the existing circulation on and off.
With a view to future applications in electronic devices and quantum innovation, scientists are concentrating on the advancement of brand-new parts that include a single layer (monolayer) of a semiconducting product. Some naturally happening products with semiconducting residential or commercial properties include monolayers of this kind, stacked to form a three-dimensional crystal. In the lab, scientists can separate these layers – which are no thicker than a single particle – and utilize them to construct electronic parts.
New residential or commercial properties and phenomena
These ultrathin semiconductors assure to provide special attributes that are otherwise extremely tough to manage, such as using electrical fields to affect the magnetic minutes of the electrons. In addition, complicated quantum mechanical phenomena happen in these semiconducting monolayers that might have applications in quantum innovation.
For the very first time, SNI scientists (University of Basel) have actually geared up an atomically thin semiconductor with superconducting contacts. In this video, they reveal the fancy fabrication procedure. Credit: C. Möller and M. Ramezani, Swiss Nanoscience Institute, University of Basel
Scientists worldwide are examining how these thin semiconductors can be stacked to form brand-new artificial products, referred to as van der Waals heterostructures. However, previously, they have actually not been successful in integrating such a monolayer with superconducting contacts in order to dig much deeper into the residential or commercial properties and peculiarities of the brand-new products.
Superconducting contacts
A group of physicists, led by Dr. Andreas Baumgartner in the research study group of Professor Christian Schönenberger at the Swiss Nanoscience Institute and the Department of Physics of the University of Basel, has actually now fitted a monolayer of the semiconductor molybdenum disulfide with superconducting contacts for the very first time. (see box)
The reason this mix of semiconductor and superconductor is so intriguing is that the specialists anticipate parts of this kind to show brand-new residential or commercial properties and physical phenomena. “In a superconductor, the electrons arrange themselves into pairs, like partners in a dance – with weird and wonderful consequences, such as the flow of the electrical current without a resistance,” describes Baumgartner, the job supervisor of the research study. “In the semiconductor molybdenum disulfide, on the other hand, the electrons perform a completely different dance, a strange solo routine that also incorporates their magnetic moments. Now we would like to find out which new and exotic dances the electrons agree upon if we combine these materials.”
Suitable for usage as a platform
The electrical measurements at the low temperature levels needed for superconductivity – simply above outright absolutely no (-273.15°C) – prove the results brought on by the superconductor; for instance, at particular energies, single electrons are no longer permitted. Moreover, the scientists discovered signs of a strong coupling in between the semiconductor layer and the superconductor.
“Strong coupling is a key element in the new and exciting physical phenomena that we expect to see in such van der Waals heterostructures, but were never able to demonstrate,” states Mehdi Ramezani, lead author of the research study.
“And, of course, we always hope for new applications in electronics and quantum technology,” states Baumgartner. “In principle, the vertical contacts we’ve developed for the semiconductor layers can be applied to a large number of semiconductors. Our measurements show that these hybrid monolayer semiconductor components are indeed possible –perhaps even with other, more exotic contact materials that would pave the way for further insights,” he includes.
Reference: “Superconducting Contacts to a Monolayer Semiconductor” by Mehdi Ramezani, Ian Correa Sampaio, Kenji Watanabe, Takashi Taniguchi, Christian Schönenberger and Andreas Baumgartner, 23 June 2021, Nano Letters.
DOI: 10.1021/acs.nanolett.1c00615
Funding: Swiss NationalScience Foundation, Swiss Nanoscience Institute (SNI) job P1701, and theERC job Top-Supra (787414)
