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In article <zyxm4pb@lynx.unm.edu> swami@chtm.eece.unm.edu (Swami srinivasan) writes:
>
>A few months back, there was talk about superconductivity in GaAs with
>Arsenic precipitates. As far as i can recall, Tc was below 30 K.
>		Danke Sehr!

It is my understanding that the original claim published in
Phys. Rev. Lett. was bogus.  The reason for it was explained to me
long ago and I've since forgotten.  I'd also be interested in the
reason if anyone knows. 

Chris Parks
parks@physics.purdue.edu

In article <zyxm4pb@lynx.unm.edu> swami@chtm.eece.unm.edu (Swami srinivasan) writes:
>
>A few months back, there was talk about superconductivity in GaAs with
>Arsenic precipitates. As far as i can recall, Tc was below 30 K.
^^^^^^^^^^^^^^^^^^^^^^
>Just wondering if there has been anything new in the past couple of 
>months (been on a 6-week vacation).

I recall reading in Science Mag. (I think) that this claim of superconductivity
in GaAs was retracted.  I believe the authors later discovered that it was the
arsenic precipitates that were showing superconductivity and not the bulk GaAs.
This is a more plausible explanation since several arsenic compounds display
superconductivity at low temperature.  In particular it is likely that if they
used lead-tin solder to attach leads to their sample that impurity compounds
such as AsPb (Tc=8.4 K) and AsSn (Tc=4.1 K) were formed.  



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parks@gibbs.physics.purdue.edu (Chris Parks) writes:
>It is my understanding that the original claim published in
>Phys. Rev. Lett. was bogus.  The reason for it was explained to me
>long ago and I've since forgotten.  I'd also be interested in the
>reason if anyone knows. 
>Chris Parks
>parks@physics.purdue.edu

Through the rumor mill I've heard that the superconductivity was real
but that the superconductor was either Ga or As.   It's too bad PRL
doesn't print retractions. (I guess it would take too many pages ;-)
-- 
---

Alison Chaiken 				alison@wsrcc.com
(510) 422-7129 [daytime] 		or chaiken@cmsgee.llnl.gov

In article <13409@creare.COM>, kwg@creare.COM (Kent Goeking) says:
>
>I recall reading in Science Mag. (I think) that this claim of
>superconductivity
>in GaAs was retracted.  I believe the authors later discovered that it was the

Could anybody give me a complete reference for this Science Mag. and the
original Phys. Rev. Lett. article?

Thanks!

Stephan

[I'm pulling GaAs-crystals from an extreme As-rich melt to investigate
the maximum As-solubility. We just found the precipitates, about 200nm
in size, so I'd like to know about this thing.... ;-)  ]




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| Stephan Petersen                               |
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In article <92227.133615IFF291@DJUKFA11.BITNET> IFF291@DJUKFA11.BITNET (Stephan Petersen) writes:
Concerning superconductivity in LT-GaAs ...
>Could anybody give me a complete reference for this Science Mag. and the
>original Phys. Rev. Lett. article?
>Stephan
I have located the original article and some comments on the validity 
of the claim in PRL.

See:
Phys. Rev. Lett., Vol. 66, pg. 3079 (1991)     <- original article
Phys. Rev. Lett., Vol. 68, pg. 551,552 (1992)  <- comments and 
                                                  almost-retraction

Chris Parks
parks@physics.purdue.edu

In article <8062@dirac.physics.purdue.edu>, parks@dirac.physics.purdue.edu
(Chris Parks) says:
>
>See:
>Phys. Rev. Lett., Vol. 66, pg. 3079 (1991)     <- original article
>Phys. Rev. Lett., Vol. 68, pg. 551,552 (1992)  <- comments and
>                                                  almost-retraction
>
>Chris Parks
>parks@physics.purdue.edu

Thanks for the references!

Stephan




+------------------------------------------------+
| Stephan Petersen                               |
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| Bitnet/EARN: IFF291@DJUKFA11                   |
| Internet:    IFF291@zam001.zam.kfa-juelich.de  |
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