Theoretical investigation into High Tc Superconductors

[NEWO]

This attachement was my dissertation, my final project for my BSc in physics, just would like a proffessional opinion.

Best wishes

newo

 

[Lonewolf]

The first thing that springs to mind is that you'd get a better response in the Condensed Matter forum, and I suspect this thread will be moved there shortly. The second is that you need more references, and to make it clear where the theory comes from.

 

[ZapperZ]

OK, I would probably be criticized for being "too hard" on this, but what the hey...

I don't think you have done what you set out to do. Have you really discussed (i) the theoretical foundation of the conventional proximity effect and (ii) the "theoretical foundation" of the proximity effect as applied to high-Tc superconductors? I looked at your paper briefly, and you were all over the place, even including some vortex discussion. Why is that?

You have not shown any experimental results to support your argument that the proximity effect in HTS is not conventional. A theory paper lacking in experimental support is a weak theory paper, especially when you are trying to make this type of argument that it is non-conventional. So the result, or at least cite a few papers, on conventional proximity effect, and then show a few papers of the giant proximity effect. Now discuss in detail why they are not the same.

Furthermore, to be able to discuss this, you also need to understand the experimental aspect of the proximity effect, i.e. was there any special crystallographic orientation that causes the proximity effect in HTS to be more "unconventional"? This is because the order parameter of HTS is anisotropic, and how these materials are oriented do make a difference in such experiments.

You also need to pass your paper through a spell checker. You also should pick up a few physics papers from PRL or PRB and see a proper format for physics citations. I strongly suggest you do not use Wikipedia as a citation. It simply shows that you haven't done a thorough literature search and rely on 2nd or 3rd hand information.

Pick up a book, such as Ed Wolf's book on Tunneling, for a very good discussion on the proximity effect in conventional superconductors.

Zz.

 

[NEWO]

no pratical or experimental work was done in this paper, the overall aim was to model what happens at the interface, when a superconductor comes into contact with a normal conducting material using the and to find the macroscopic condensate wavefunction using the gross pitevski type equations. unfortunately the resulting equations are not solvable.

 

[ZapperZ]

no pratical or experimental work was done in this paper, the overall aim was to model what happens at the interface, when a superconductor comes into contact with a normal conducting material using the and to find the macroscopic condensate wavefunction using the gross pitevski type equations. unfortunately the resulting equations are not solvable.

You missed what I said.

I know that this is a purely theoretical paper, but you were indicating that the proximity effect in HTS is not the same as conventional. How do you know? What possible sources do you have to make such a claim? This is where you NEED to cite experimental results of OTHERS to support your claim.

You need to pick up some actual physics papers, especially theoretical papers in condensed matter, and see that many of them cite experimental results to bolster their arguments. You can't work in theory and be in a complete vacuum with regards to experimental results, especially in the HTS field, because the experimental results are the ones guiding the theory!

Besides that, your "theory" is still lacking in a proper development. You never discuss why you think this is the right track to pursue.

Zz.

 

[NEWO]

my understanding came from a couple of papers.

1. Vortex matter in the charged Bose liquid at absolute zero by V.V.Kabanov and A.S. Alexandrov
2.Giant Proximity effect-Physical review letters 2004 volume 93 number 15.

as stated in my references, thanks for you constructive criticism any way .

 

[ZapperZ]

my understanding came from a couple of papers.

1. Vortex matter in the charged Bose liquid at absolute zero by V.V.Kabanov and A.S. Alexandrov
2.Giant Proximity effect-Physical review letters 2004 volume 93 number 15.

as stated in my references, thanks for you constructive criticism any way .

Maybe if you won't listen to me, you will listen to what your advisor has done. I happen to know quite well his work, especially his polaron/bipolaron scenario of HTS.

If you look at these two papers, for example:

1. A. S. Alexandrov, Phys. Rev. Lett. 96, 147003 (2006)
2. A. S. Alexandrov and A. M. Bratkovsky, Phys. Rev. Lett. 82, 141 (1999)

You'll notice that your advisor puts SEVERAL citations of experimental results (not simply papers that cited other papers of the results) right at the very beginning! This is because at this stage, you can no longer rely on 2nd or 3rd hand news. You have to go right at the source! In fact, throughout the paper, especially the first one, he even had the experimental data from some source to compare it with the theoretical model.

While it is a common practice in string theory, in condensed matter, a paper theory paper devoid of any explicit reference to experimental evidence to back up its claim will often evaporate into oblivion, if it gets published in the first place.

There is also one other point that I forgot to make. If you give this to someone who has a background in physics, but has never heard of what a "proximity effect" is, do you think that person would have been able to understand what it is after reading your paper? Forget about the unconventional proximity effect in HTS. Do you think you have sufficiently described the conventional proximity effect, including Andreev reflection, in your paper?

Zz.

 

[NEWO]

no no you don't understand, I do take your ideas and I would have used them if I didn't already hand it in lol. I was just trying to get some ideas of what I should have done and you have so thank you. As it happens i already did.

Also I just followed instructions laid out by my professor. I don't think that this paper would be published anyway I'm just an undergraduate, who would listen to me anyway lol!

Thanks for your interest.