Superconductivity could form at high temperatures in layered 2D crystals

July 28, 2014, University of California - San Diego

An elusive state of matter called superconductivity could be realized in stacks of sheetlike crystals just a few atoms thick, a trio of physicists has determined.

Superconductivity, the flow of electrical current without resistance, is usually found in materials chilled to the most frigid temperatures, which is impractical for most applications. It's been observed at higher temperatures–higher being about 100 kelvin or minus 280 degrees below zero Fahrenheit–in copper oxide materials called cuprate superconductors. But those materials are brittle and unsuitable for fabricating devices like circuits.

In a paper published in Nature Communications the week of July 28, Michael Fogler and Leonid Butov, professors of physics at the University of California, San Diego, and Konstantin Novoselov, Nobel laureate in physics and professor at the University of Manchester, propose a design for an artificially structured material that should support superconductivity at temperatures rivaling those seen for cuprates.

They considered a material made by interleaving two different types of crystal, one a semiconductor compound and the other a type of insulator. Two one-atom thick layers of the semiconductor compound molybdenum disulfide would be separated by a few-atom thick spacer made of boron nitride, and surrounded by additional boron nitride cladding.

This sets up a situation in which electrons and "holes" left by a missing electrons would accumulate in separate layers of the semiconductor compound in response to an electrical field. And yet these separated electrons and holes would be bound, at a distance, in states called indirect excitons.

These indirect excitons would form a gas with vanishing viscosity. That is, below a certain temperature, the gas would become superfluid. The physicists determined that superfluidity of indirect excitons would set up countercurrents that would not dissipate, a phenomenon called counterflow superconductivity.

Superfluidity and superconductivity are macroscopic manifestations of quantum phenomena, which are usually seen at the smallest physical scales.

The proposed design is an initial blueprint, the authors write. Their analysis reveals a general principle for creating "coherent states" like superfluidity and that would emerge in similar materials created with layers of other semiconductor compounds such as tungsten disulfide or tungsten diselenide as well.

Such van der Waals structures are the subject of many investigations; this new analysis demonstrates that they also provide a new platform for exploring fundamental quantum phenomena.

Practical uses are possible as well; these materials could be used to develop electronic and optoelectronic circuits.

Explore further: Finding the 'heart' of an obstacle to superconductivity

Related Stories

Finding the 'heart' of an obstacle to superconductivity

July 23, 2014

A team at Cornell and Brookhaven National Laboratory has discovered that previously observed density waves that seem to suppress superconductivity are linked to an electronic "broken symmetry," offering an important clue ...

Superconducting secrets solved after 30 years

June 17, 2014

( —A breakthrough has been made in identifying the origin of superconductivity in high-temperature superconductors, which has puzzled researchers for the past three decades.

Discovery furthers understanding of superconductivity

May 28, 2013

( —Physicists at the University of Arkansas have collaborated with scientists in the United States and Asia to discover that a crucial ingredient of high-temperature superconductivity could be found in an entirely ...

Recommended for you

Correlated nucleons may solve 35-year-old mystery

February 20, 2019

A careful re-analysis of data taken at the Department of Energy's Thomas Jefferson National Accelerator Facility has revealed a possible link between correlated protons and neutrons in the nucleus and a 35-year-old mystery. ...

CMS gets first result using largest-ever LHC data sample

February 15, 2019

Just under three months after the final proton–proton collisions from the Large Hadron Collider (LHC)'s second run (Run 2), the CMS collaboration has submitted its first paper based on the full LHC dataset collected in ...


Adjust slider to filter visible comments by rank

Display comments: newest first

1 / 5 (6) Jul 28, 2014
Superconductivity could form at high temperatures in layered 2D crystals
It has been already observed - but never attempted to replicate. BTW If we constrain the motion of electrons to single fiber, you can achieve the superconductivity at even higher temperatures - without Cooper pairs and all this nonsense in Nobel prized theories. It's known already for thirty years - but never researched at peer reviewed journals level as well. Why? The contemporary physicists don't research the things, until they've no theory for it for not to threat the occupation, grants and social status of theorists lobby.
1 / 5 (6) Jul 28, 2014
The whole basis of superconductivity is in constraining the motion of charge carriers to lower number of dimensions, than this one, which they're using to occupy. Due to quantum fluctuations of vacuum the motion in the remaining dimension/direction becomes less constrained. There are two main ways how to achieve it: with pushing force of another neighboring charge carriers and with pulling force of another, already aligned charged particles. For example inside of graphene the electrons are held at plane not with repulsion of another electrons from both sides, but simply with attractive force of protons within carbon atoms. The result is the same, like the constraining the motion of electrons inside of layers of superconductors. The existing theories of low-temperature superconductivity focused to one aspect of the electron motion in Cooper pairs and missed the answering the basic question: WHY these pairs are formed there at all.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.