Superconductivity at "ambient temperature"?

[Wrichik Basu]

On 23rd July, 2018, physicists from Indian Institute of Science (IISc) Bangalore, said that they had discovered superconductivity at room temperature. The paper in arxiv aroused doubts in the scientific world, but nothing was said after that.

However, the team has reviewed the paper to a new version on 28 May this year, stirring new discussions all over newspapers.

Here is the paper on arxiv:
https://arxiv.org/abs/1807.08572v3
It's a long paper and I haven't read through it. But here are two news articles from a credible news agency:
https://www.thehindu.com/sci-tech/s...ivity-at-room-temperature/article27271786.ecehttps://www.thehindu.com/sci-tech/s...room-temperature-pressure/article27246496.ece
What do you think?

 

[phinds]

What do you think?

I'll believe it if and when I see a lot more evidence and I'm not planning on holding my breath.

 

[Bcavender]

Getting this out of the lab and into wire production would revolutionize alternator/motor performance.

The big question is ... are they on the level with real materials?

Lots of research has besmirched the scientific community promising results are "only five years away".

 

[Vanadium 50]

But here are two news articles from a credible news agency

The only cheerleading of this result has been in the Indian press.

 

[Nik_2213]

"Extraordinary claims require extraordinary evidence"
IMHO, they're using plausible ingredients and tech.
But, remembering unfortunate stuff such as 'Cold Fusion' and 'N-Rays', ain't so until repeatably reproducible...

Also, given the vagaries of nano-structures, there may be a lonnnng learning curve...

 

[Bcavender]

No one on this planet wants to buy 14 gauge magnet wire with 10^-3 ohms per loop-mile more than this engineer. But I have to agree with Nik about extraordinary claims. (And, to be honest, "The Hindu" website is about science-cred-focused as Yahoo.)

After nearly 50 years of keeping up with EE tech/science, I am eternally hopeful, but pretty burned out with billions spent on mega-grants, dead end pilot projects, palatial university buildings, labs and comfortable offices and occupants that come up with an occasional interesting concept or two, but almost NEVER any really useful breakthrough that shows up in an electrical supply house ready to go to the field and do some process 50% better that the base technology that was available 50 years before I was born.

The negative feedback loop in the funding/performance process is disconnected and thus the entire system is out of control.

Like our "forever wars", "forever research" that produces nothing but jobs for those directly esconched in the system that return little or nothing to Joe and Jane, plumber and bookkeeper, that can't afford a house, let alone kids ... well you get my drift.

Our people would be better off if they could spend their money as they see best ... and the best of the scientists would be getting their funding from someone they could convince that their developments have real, deliverable value. Or at least 10% more value than the money plunked down to develop the science.

Rant off ...

 

[Nik_2213]

"Rant off ..."

Funnily enough, I could say much the same about space exploration.

Fifty years since Neil Armstrong. Forty since the BIS' 'Daedalus Report'.

Saturn supplanted by the 'superior' Shuttle, which no longer flies. ISS both late and incomplete, to exasperation of contributing nations. Current design out-weighed by the zillion paper-studies...

And then Boeing announce their wondrous, revolutionary, ground-breaking, TNG 'Starliner' design.
I was nearly banned from A.N.Other forum for expostulating, "That's not even a 'Currach', that's a ruddy Coracle !"

Upside, un-crewed probes have ventured hither and yon, delivering wondrous data, and the orbital observatories' findings continue to astonish. Ground-based observatories deliver wonders upon wonders, too...

Downside, weary of no crewed missions beyond LEO, I resigned my BIS membership several years ago...
/

 

[Bcavender]

I have a ME Entrepreneur friend that worked for Honeywell on the Moonshot (after a naval career serving on the Nautilus). Quite an accomplished fellow.

We both arrived on this same wavelength recently about the endemic problem of increasing dollars spent and decreasing value returned over the last three decades.

Our consensus is that something has to give in terms of proper consumption and production of value ... or it will be hard to hold the Country together.

Certainly growing this out of control system by offering "free" everything to everyone will only accelerate the severity.

Direction is more important than speed.

 

[phinds]

 

[Nik_2213]

Must be said proven 'ambient temperature superconductivity', on however minute a scale, would so up-end the paradigm of increasingly arcane cuprate-ish analogues and their so-slowly rising TCs.

I don't know enough to do more than wonder about mechanisms beyond herding 'Cooper Pairs'...

 

[StanislavD]

One important note about the superconductivity (SC) in the Ag/Au nanostructure: the result is perfectly in line with the SC approach of local electron pairing and Bose-Einstein-Condensation (BEC) of the pairs as bosons.
In the indian paper the density of the Ag-clusters corresponds to the bosonic density, which is necessary for the BEC at temperature ≈ 286 K, see Eq. (2.3), (2.4), (2.5) in https://hal.archives-ouvertes.fr/hal-02388588v2/document . The local pairing within every Ag cluster occurs because the work function (W) of Au is larger than W of Ag by roughly 0.6 eV. This provides a Volta potential ≈ 0.6 eV at interface of Ag/Au, so every Ag cluster gets electron depletion and, thus, becomes a 3D potential well. This potential well provides favorable local states inside every Ag cluster, so stable singlet pairs can occur. At BEC temperature the singlet pairs condense into macroscopically coherent BEC, and, thus, become nonlocal and nondissipative.

 

[Vanadium 50]

The more relevant issue seems to be that in 3 years the result seems not to have been replicated, not have samples been sent to independent labs to verify superconductivity. A resistivity drop is the beginning of the story, not the end. Three years after Bednorz and Muller there were dozens (hundreds?) of labs working on cuprate superconductivity.

 

[StanislavD]

The more relevant issue seems to be that in 3 years the result seems not to have been replicated, not have samples been sent to independent labs to verify superconductivity. A resistivity drop is the beginning of the story, not the end. Three years after Bednorz and Muller there were dozens (hundreds?) of labs working on cuprate superconductivity.

The weak reproducibility of results indicates, that the electronic structure of such nanostructures is very sensitive to fast degradation processes. So one cannot reproduce the result even in one the same sample. However, it does not deny the initial measurement results.

 

[Vanadium 50]

How many years should we wait for replication? If three's not enough, should it be 10? 50? 100? Even if the sample was somehow unique, how come it hasn't been sent to another lab and its properties verified?

To be clear, the only evidence for superconductivity is a drop of resistivity of a few percent, after which the proponents claimed that only a few percent of their sample was actually superconducting. They do not see zero resistivity. They do not see the Meissner effect. I do not believe they saw a change in electronic heat capacity, although I admit I am fuzzy on that.

 

[StanislavD]

How many years should we wait for replication? If three's not enough, should it be 10? 50? 100? Even if the sample was somehow unique, how come it hasn't been sent to another lab and its properties verified?

To be clear, the only evidence for superconductivity is a drop of resistivity of a few percent, after which the proponents claimed that only a few percent of their sample was actually superconducting. They do not see zero resistivity. They do not see the Meissner effect. I do not believe they saw a change in electronic heat capacity, although I admit I am fuzzy on that.

I agree, there is something to do and to improve in the story. Generally speaking, nanostructures may be a promising way to room temperature SC.