Semiconductor Electrically Connected to Superconductor

The monolayer of molybdenum disulfide (MoS2) is sandwiched between two protecting layers of boron nitride (hBN), with molybdenum rhenium (MoRe) contacts extending by means of the higher one. A layer of graphene (gate) is used for electrical management. Credit score: Mehdi Ramezani, Swiss Nanoscience Institute, College of Basel

For the primary time, College of Basel researchers have outfitted an ultrathin semiconductor with superconducting contacts. These extraordinarily skinny supplies with novel digital and optical properties might pave the way in which for beforehand unimagined functions. Mixed with superconductors, they’re anticipated to present rise to new quantum phenomena and discover use in quantum know-how.

Whether or not in smartphones, televisions or constructing know-how, semiconductors play a central position in electronics and subsequently in our on a regular basis lives. In distinction to metals, it’s potential to regulate their electrical conductivity by making use of a voltage and therefore to change the present circulation on and off.

With a view to future functions in electronics and quantum know-how, researchers are specializing in the event of recent elements that include a single layer (monolayer) of a semiconducting materials. Some naturally occurring supplies with semiconducting properties function monolayers of this type, stacked to kind a three-dimensional crystal. Within the laboratory, researchers can separate these layers – which are not any thicker than a single molecule – and use them to construct digital elements.

New properties and phenomena

These ultrathin semiconductors promise to ship distinctive traits which might be in any other case very tough to manage, equivalent to using electrical fields to affect the magnetic moments of the electrons. As well as, complicated quantum mechanical phenomena happen in these semiconducting monolayers which will have functions in quantum know-how.


For the primary time, SNI researchers (College of Basel) have outfitted an atomically skinny semiconductor with superconducting contacts. On this video, they present the flowery fabrication course of. Credit score: C. Möller and M. Ramezani, Swiss Nanoscience Institute, College of Basel

Scientists worldwide are investigating how these skinny semiconductors could be stacked to kind new artificial supplies, often called van der Waals heterostructures. Nonetheless, till now, they haven’t succeeded in combining such a monolayer with superconducting contacts so as to dig deeper into the properties and peculiarities of the brand new supplies.

Superconducting contacts

A workforce of physicists, led by Dr. Andreas Baumgartner within the analysis group of Professor Christian Schönenberger on the Swiss Nanoscience Institute and the Division of Physics of the College of Basel, has now fitted a monolayer of the semiconductor molybdenum disulfide with superconducting contacts for the primary time. (see field)

The rationale why this mix of semiconductor and superconductor is so attention-grabbing is that the specialists anticipate elements of this type to exhibit new properties and bodily phenomena. “In a superconductor, the electrons prepare themselves into pairs, like companions in a dance – with bizarre penalties, such because the circulation of {the electrical} present with out a resistance,” explains Baumgartner, the challenge supervisor of the research. “Within the semiconductor molybdenum disulfide, alternatively, the electrons carry out a totally completely different dance, an odd solo routine that additionally incorporates their magnetic moments. Now we want to discover out which new and unique dances the electrons agree upon if we mix these supplies.”

Appropriate to be used as a platform

{The electrical} measurements on the low temperatures required for superconductivity – simply above absolute zero (-273.15°C) – present clearly the consequences brought on by the superconductor; for instance, at sure energies, single electrons are now not allowed. Furthermore, the researchers discovered indications of a powerful coupling between the semiconductor layer and the superconductor.

“Robust coupling is a key factor within the new and thrilling bodily phenomena that we anticipate to see in such van der Waals heterostructures, however had been by no means in a position to reveal,” says Mehdi Ramezani, lead writer of the research.

“And, after all, we all the time hope for brand spanking new functions in electronics and quantum know-how,” says Baumgartner. “In precept, the vertical contacts we’ve developed for the semiconductor layers could be utilized to numerous semiconductors. Our measurements present that these hybrid monolayer semiconductor elements are certainly potential –even perhaps with different, extra unique contact supplies that might pave the way in which for additional insights,” he provides.

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 Basis, Swiss Nanoscience Institute (SNI) challenge P1701, and theERC challenge High-Supra (787414)

By Rana

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