Thinnest Superconducting Metal Created by Physicists at The University of Texas at Austin

June 8, 2009

AUSTIN, Texas — A superconducting sheet of lead only two atoms thick, the thinnest superconducting metal layer ever created, has been developed by physicists at The University of Texas at Austin.

Dr. Ken Shih and colleagues report the properties of their superconducting film in the June 5 issue of Science.

Superthin Superconductor

This is a scanning tunneling microscope image of the 2-atom thick lead film. The inset is a zoomed view showing the atomic structure.

Superconductors are unique because they can maintain an electrical current indefinitely with no power source. They are used in MRI machines, particle accelerators, quantum interference devices and other applications.

The development of the thin superconducting sheets of lead lays the groundwork for future advancements in superconductor technologies.

"To be able to control this material-to shape it into new geometries-and explore what happens is very exciting," says Shih, the Jane and Roland Blumberg Professor in Physics. "My hope is that this superconductive surface will enable one to build devices and study new properties of superconductivity."

In superconductors, electrons move through the material together in pairs, called Cooper pairs.

One of the innovative properties of Shih's ultra-thin lead is that it confines the electrons to move in two dimensions, or one "quantum channel," like ballroom dancers gliding across the floor. Uniquely, the lead remains a good superconductor despite the constrained movement of the electrons through the metal.

Shih and his colleagues used advanced materials synthesis techniques to lay the two-atom thick sheet of lead atop a thin silicon surface. The lead sheets are highly uniform with no impurities.

"We can make this film, and it has perfect crystalline structure-more perfect than most thin films made of other materials," Shih says.

For more information, contact: Lee Clippard, College of Natural Sciences, 512-232-0675; Dr. Chih-Kang “Ken” Shih, professor of physics, 512-471-6603, shih@mail.utexas.edu

21 Comments to "Thinnest Superconducting Metal Created by Physicists at The University of Texas at Austin"

1.  OddesE said on June 9, 2009

At what temperature does this effect occur? I'm guessing not at room temperature?

2.  Milind Doshi said on June 10, 2009

Hi,
Congratulations on your invention,
I have a question regarding the application of this metal. I am working on launching a photovoltaic production facility. However I am curious if your product can be used as a flexible substrate on which we can can quote copper indium gallium and selenide, in order to harness the Sun's energy.

3.  Jeroen said on June 10, 2009

First. Nice work! And second. At what temperatures were these experiments conducted, in relation for the use of the given applications?

Jeroen

4.  Jungdae Kim said on June 10, 2009

Thank you for all your interest in our work.

All of the measurements were done at the temperature range of 3.4 ~ 6 K. A home-built low temperature scanning tunneling microscope was used to probe superconductivity of the sample.

You can find more detailed information of the paper online.

5.  Bruce Whiteside said on June 11, 2009

So is this "quantun channel" like a nanostructure waveguide at the electron's or electron pairs' wavelength? If so, that model might lead to superconducting advances.

Ditto on the temperature question.

6.  DANTE SBRAGIA said on June 11, 2009

Very interesting, but at what temperature does it work?

Is it affected by alternated magnetic fields?

Best regards,
Dante

7.  Mike said on June 11, 2009

As it is still made up of lead I would expect it to have the same critical temperature of 7.2 k, although the thickness of the material could have some affect on that temperature.

8.  D H said on June 11, 2009

I would think it could be posible to create nonvolital memory; by creating small wells in a silicon substrate, depositing the lead superconducting layer in the wells, putting circuitry contacts to the layer, and then you could charge and read the information stored there. This would be perfect for things like space probes, satalites, etc. which are in the cold of space. And if it worked at room temprature, it would really be something impresive, cheap, high density, no more complicated designs, and it would be just about as fast as you can get within our current understanding of physics.

9.  abduljabbar said on June 11, 2009

that's very good .... god bless you.

10.  Trout said on June 11, 2009

You can read the article online. Temperatures were below 7 K (-266 degrees C).

11.  Ken Shih said on June 11, 2009

These superconducting films have transition temperature below 7 Kelvin. In fact, the transition temperature is thickness dependent. At 4 ML or higher, the Tc is above 6 K. But at 2 ML, the transition temperature is only 4.9K. Moreover, with a slight structural strain, Tc drops to even lower temperature.

For some devices such as superconducting quantum interference devices (SQUID), the ability to engineer the superconducting films with atomic precision may improve the performance. For exotic devices such as Josephson Junction based superconductor quantum bits, such a capability - making superconduting films with atomic scale control - may significantly reduce the noise problem.

12.  Faiyaz Muhammed Pasha said on June 11, 2009

Excellent.
We should now be able to build very high load electricity storage devices?
Great work.

13.  Don M Sierra said on June 12, 2009

Can this film be used to transmit information...faster than the speed of light?

14.  Greg said on June 12, 2009

Can you please provide a citation to the relevant article in a peer-reviewed publication? This press release is nice, but it should at least either have a copy of the abstract or a link to the article and doi number so those of us interested can get the real details (fabrication methods, temperature of operation, area over which this effect occurred, characterization results, etc).

15.  Jungdae Kim said on June 12, 2009

Thank you for all your interest~!
All measurements were done at 3.4 ~ 6 K. Home-built low temperature scanning tunneling microscope was used to probe superconductivity of the sample.

16.  Jungdae Kim said on June 12, 2009

Definitely, superconductivity of the sample will be affected by external magnetic field. How vortex induced by magnetic field changes superconductivity of the ultra thin superconductor is one of our next experiment. If you are interested in more details of the paper, I would like to recommend you to read our paper, Science Vol.324 p.1314 - 1317 (DOI: 10.1126/science.1170775).

Thanks

17.  Jungdae Kim said on June 12, 2009

Sorry, I missed one of the questions posted at the beginning. Ultra thin Pb film (~ 6 angstrom) was grown on Si(111) substrates at low temperature (~100K). Unfortunately, this film is not stable at room temperature which means film will break down into much thicker islands instead of flat film when sample temperature is higher than 200K.

Thanks again~!

18.  Steve Nordquist said on June 13, 2009

Great! RoHS (Restriction of Hazardous Substances) devices can be 300 angstroms or more and still pass testing. What was the pair density again?

LOL "product," Milind: License the empirical method and have a good condensed matter scientist and some good evaporation coolers handy for putting your James Bond solar island to work. Maybe Zaha Hadid and some equatorial African pols.

19.  angela said on June 13, 2009

what are the pros and cons of this invention?

20.  alexander brandon said on June 19, 2009

I would like to know, of what temperature is the superconductivity working? I mean in Celsius degrees.
Sincerely yours,
Alexander Brandon

21.  mehmet kaplan said on June 27, 2009

First of all, congrats. Really nice work. What's the efficiency for energy transmitting? What's the pressure you've been using on the superconductor?