Discovery furthers understanding of superconductivity

May 28, 2013

(Phys.org) —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 different class of materials.

"There have been more than 60,000 papers published on high-temperature superconductive material since its discovery in 1986," said Jak Chakhalian, professor of physics at the University of Arkansas. "Unfortunately, as of today we have zero theoretical understanding of the mechanism behind this enigmatic phenomenon. In my mind, the high-temperature superconductivity is the most important unsolved mystery of ."

Superconductivity is a phenomenon that occurs in certain materials when cooled to extremely low temperatures such as negative-435 degrees Fahrenheit. High-temperature superconductivity exists at negative-396 degrees Fahrenheit. In both cases drops to zero and complete expulsion of magnetic fields occurs.

Superconductors have the ability to transport large electrical currents and produce high magnetic fields, which means they hold great potential for and .

The recent finding by the University of Arkansas-led team is important to further understand superconductivity, Chakhalian said.

An article detailing the finding, "Zhang-Rice physics and anomalous copper states in A-site ordered perovskites" was published Monday, May 13, in Scientific Reports, an online journal published by the journal Nature.

Derek Meyers, a doctoral student in physics at the U of A, found that the way electrons form in superconductive material—known as the Zhang-Rice singlet state—was present in a that is very different from .

"There is now a whole different class of materials where you can search for the enigmatic superconductivity," Chakhalian said. "This is completely new because we know that the Zhang-Rice quantum state, which used to be the hallmark of this high-temperature superconductor, could be found in totally different crystal structures. Does it have a potential to become a novel superconductor? We don't know but it has all the right ingredients."

Meyers was the lead researcher. Srimanta Middey, a postdoctoral research associate at the university and Benjamin A. Gray, a , performed the theoretical calculations and analyzed the experimental data obtained at the X-ray synchrotron at Argonne National Laboratory near Chicago.

In the mid-1980s, physicists determined that all high-temperature superconductive material must contain copper and oxygen and those elements arrange two-dimensionally.

In this material the electrons combine into a unique quantum state called the Zhang-Rice singlets, Chakhalian explained.

"I can make a closed circuit out of the superconducting material, cool it down and attach a battery that starts the flow of the electrons. The current goes around the loop. Then I detach it and leave it. Hypothetically, 1 billion years later the flow of electrons is guaranteed to be exactly the same—with no losses," he said. "But the problem is we don't know if we are even using it right. We have no microscopic understanding of what is behind it."

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More information: www.nature.com/srep/2013/13051… /full/srep01834.html

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User comments : 17

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Birger
4.5 / 5 (2) May 28, 2013
So A-site ordered perovskites are of interest. The article forgets to explain what exactly "A-site ordered perovskites" are.
johanfprins
1 / 5 (10) May 28, 2013
Derek Meyers, a doctoral student in physics at the U of A, found that the way electrons form in superconductive material—known as the Zhang-Rice singlet state—was present in a chemical compound that is very different from conventional superconductors.
Further proof that the mainstream physicists doing research on high temperature SC have no clue, and have been barking up the wrong tree since 1986: In fact since 1958. Zhang-Rice has nothing to do with SC!

The worst is that when pointing out to them that the cat is in another tree, they refuse to even look at the other tree since it does not suit their preconceived and wrong ideas on what the mechanism for SC is.

A mechanism has been known since 2005 and has been fitted to available data of all SC materials: For example YBCO, lead, p-type diamond. It has NOTHING to do with phonon-coupling of electron-pairs; and no other model fits the data better. A summary can be seen here:

http://www.cathod...nism.pdf
ValeriaT
1 / 5 (5) May 29, 2013
we have zero theoretical understanding of the mechanism behind this enigmatic phenomenon. In my mind, the high-temperature superconductivity is the most important unsolved mystery
In my mind not - the superconductivity is the result of highly mutually compressed electrons within superconductors, where their repulsive forces overlap and compensate mutually in wide extent, so that the electrons can move freely. It's a similar effect, like if you squeeze the jelly balls inside fist - the balls will move freely from a moment, when they will form an homogeneous continuum.
johanfprins
1 / 5 (6) May 29, 2013
the superconductivity is the result of highly mutually compressed electrons within superconductors, where their repulsive forces overlap and compensate mutually in wide extent,
When this happens you get an "impurity band" and NORMAL conduction by wave-packets. There is enough published data on SC which prove that where-as pressure can increase the critical temperature, it can also cause a transition to normal conduction at higher pressures. Thus your model is not generally correct!
Minich
1 / 5 (2) May 31, 2013
we have zero theoretical understanding of the mechanism behind this enigmatic phenomenon. In my mind, the high-temperature superconductivity is the most important unsolved mystery

In my mind the high-temperature superconductivity is the most important SOLVED mystery.
BY means of NEW one electron band modified theory by Minich :)
IT is as simple to understand as the atomic theory to a barmaid.
johanfprins
1.8 / 5 (5) May 31, 2013
we have zero theoretical understanding of the mechanism behind this enigmatic phenomenon. In my mind, the high-temperature superconductivity is the most important unsolved mystery

In my mind the high-temperature superconductivity is the most important SOLVED mystery.
BY means of NEW one electron band modified theory by Minich :)
IT is as simple to understand as the atomic theory to a barmaid.
Superconduction does not occur by charge-carriers that are generated within an electron-energy band. Only normal conduction can occur in this manner!

johanfprins
1 / 5 (3) May 31, 2013
Because I'm talking about compression of electrons only, not about compression of atoms. This is indeed a difference - in some cases the squeezing of atoms could make their electrons more separated each other instead. For example, the sodium metal changes into transparent insulator under high pressure.
I do not care whether you squeeze the atoms, or the electrons, or both: Your model is wrong. It is only correct in one respect and that is that the charge-carriers required for SC must reach and exceed a critical density for SC to occur. The reason for that has, however, nothing to do with your silly model!
ValeriaT
1 / 5 (3) May 31, 2013
I do not care whether you squeeze the atoms, or the electrons, or both: Your model is wrong.
You don't care about my explanation, I don't care about your reply. The electrons are the only charge-carriers for SC and they can reach critical density only via squeezing. This indeed has very much to do with my model.
johanfprins
1 / 5 (3) May 31, 2013
You don't care about my explanation, I don't care about your reply. The electrons are the only charge-carriers for SC and they can reach critical density only via squeezing.


We have been through your deluded models many times before and I have given you ample proof that you are wrong! I have better things to do than to contemplate ducks swimming and farting within a non-existent "aether" or, for that matter, to try and teach you simple solid state physics. Just accept it: You do not have the required grey matter between your ears!
PPihkala
3 / 5 (2) May 31, 2013
"Unfortunately, as of today we have zero theoretical understanding of the mechanism behind this enigmatic phenomenon. In my mind, the high-temperature superconductivity is the most important unsolved mystery of condensed matter physics."

I think LENR is the more important ie most important mystery to solve and to be taken to practical use. And in LENR we know that it will occur at practical temperatures, while SC, even if made to work at higher temps, has less uses that LENR can have. SC, like hydrogen, is the carrier of energy, while LENR can replace other energy sources.
johanfprins
1 / 5 (3) Jun 01, 2013
while LENR can replace other energy sources.
What the hell is LENR?
jsdarkdestruction
5 / 5 (1) Jun 01, 2013
low-energy nuclear reactions
(just saying what it stands for, I wont comment on it or that guy who's talking about its post.)
ValeriaT
1 / 5 (3) Jun 01, 2013
What the hell is LENR?
Which planet are you coming from? No further questions are needed - the ignorants who don't know about it already belong into recent era and they will never learn the new tricks.
I think LENR is the more important ie most important mystery to solve and to be taken to practical use.
Definitely yes - we first need to have some reliable energy source - just after then we should think, how to distribute it without ohmic loss from place to place. Not to say, the finding of mobile/distributed cold fusion source of energy would relativize the need of development of superconductors or even the energy grids as a whole. What we actually need are the lightweight powerful batteries - not the gigantic ITERs and the pile of superconductor wires connecting them at wast distance. These priorities are clearly given already: research smarter, not harder.
johanfprins
2.3 / 5 (6) Jun 01, 2013
low-energy nuclear reactions
(just saying what it stands for, I wont comment on it or that guy who's talking about its post.)

Thank you. I just hate to remember abbreviations: There are more important things to do, or else one will end up being demented like ValeriaT.
oliver_jovanovic_99
1 / 5 (2) Jun 08, 2013
Advice needed

I think I have the idea how to increase electrical conductivity of standard conductors at room temperatures.
What can I do with that?

Thank you

ValeriaT
1 / 5 (2) Jun 08, 2013
I think I have the idea how to increase electrical conductivity of standard conductors at room temperatures. What can I do with that?
This is very cool finding, so you should keep it cool. The conductivity of most standard conductors rises when you cool them.
oliver_jovanovic_99
1 / 5 (2) Jun 08, 2013
@ Valeria T
please be gentle :)
"like if you squeeze the jelly balls inside fist - the balls will move freely"

on more serious note, i would really like to read your work. where can i find it?

if you are interested in my "fantasies", You can google it.

oliver r jovanovic

(it is not about conductivity)