Talk:Quantum Hall effect

message: Ther term 'hall conductivity' is never defined. 
The direction of magnetic field and that of the applied voltage is never mentioned.
People use terms like longitutal conductivity and horizontal resistance in QHE studies.
None of these terms are defined in this article.  —Preceding unsigned comment added by 71.60.19.4 (talk) 02:17, 25 December 2009 (UTC)
thread_title: Missing Contents

message: The  beginning of this article states that QHE is observed in 2d electron systems "subjected to low temperatures and strong magnetic fields". Recent developments (e.g. []) have shown the QHE in room temperature conditions. Perhaps a good replacement would be the following:
"The quantum Hall effect (or integer quantum Hall effect) is a quantum-mechanical version of the Hall effect. It is observed in two-dimensional electron systems usually subjected to low temperatures and strong magnetic fields, in which the Hall conductivity σ takes on the quantized values
    \sigma = \nu \; \frac{e^2}{h}, 
where e is the elementary charge and h is Planck's constant. Recently, the quantum hall effect has also been observed at room temperature in graphene."
Any comments before changing? Or anybody have a better/more apt place to put the graphene developments?  -One Son of Ole (talk) 17:56, 26 September 2008 (UTC)
thread_title: Graphene: QHE at room temp. 

message: The statement that the integer effect can be "simply explained" is false. Simple Landau quantisations would p[roduce precisely quantised plateaus of precisely zero width. The finite width of plateaus requires disorder (and inherently electron scattering, in the face of which precise quantisation is surprising. This article does not explain the origin of this precision nor the not infinitesimal width of plateaus..  —Preceding unsigned comment added by 79.67.70.191 (talk) 20:12, 3 May 2009 (UTC)
thread_title: =

message: Quantum Hall effect was not predicted by Ando et al in 1975.  I have removed that statement.  —Preceding unsigned comment added by 78.86.83.158 (talk) 11:24, 19 July 2009 (UTC)
thread_title: ==

message: It's been a long time, but I remember it differently. I seem to remember, however. When the Nobel Prize was awarded, there was always spoken of resistance, not of the conductivity. Ok, I'll look it up again. --Franz Scheerer (Olbers) (talk) 12:00, 3 November 2013 (UTC)
thread_title:  I remember it differently 

message: The animation of the Landau levels as a function of B is nice but wrong. The fermi energy oscillates with them.  — Preceding unsigned comment added by 129.27.161.141 (talk) 07:48, 20 January 2012 (UTC)
replies: text: Several people have pointed out problems with the animation. However, I feel it is still useful despite the issues, and I think we should leave it in place until someone develops a better version. SPattalk 23:09, 2 August 2014 (UTC)
thread_title:  Animation nice but wrong 

message: Can I mention once again that, although the noncommutative work by Bellisard is nice, it is not generally considered to be the only explanation of the quantum hall effect.  Indeed no one doubted the physics was correct once the original Laughlin gauge argument was in place and Halperin gave a few more details.   Few people even know of this work, and to have it feature so prominently in this wikipedia page is just a misrepresentation that keeps re-appearing.  — Preceding unsigned comment added by 81.110.91.126 (talk) 20:12, 13 July 2016 (UTC)
thread_title:  Bellisard 

message: Hello fellow Wikipedians,
I have just modified  on Quantum Hall effect. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
*Added archive http://web.archive.org/web/20070304025657/http://parthe.lpthe.jussieu.fr:80/poincare/textes/novembre2004.html to http://parthe.lpthe.jussieu.fr/poincare/textes/novembre2004.html
*Added archive http://web.archive.org/web/20110707025318/http://hrma.physics.sjtu.edu.cn/PhysicsHorizon/25yearsQHE-lecture.pdf to http://hrma.physics.sjtu.edu.cn/PhysicsHorizon/25yearsQHE-lecture.pdf
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thread_title:  External links modified 

message: The introductory paragraphs are really technical and don't explain anything.
What's the experimental setup? Picture? Geometry? Particles? Participants? Definitions?
Incoherent.
2001:67C:10EC:5787:8000:0:0:8A7 (talk) 10:05, 19 February 2019 (UTC)
thread_title:  Really bad article 

message: I am part of a group of Physics students who are finishing the degree this year. We have been asked to modify a Wikipedia article and we have chosen quantum hall effect topic. We have made some brief notes related to the integer quantum hall effect and we would like to add them to the article. In this notes it is explained the explicit derivation of the landau energy expression from Schrödinger’s equation and it is derived explicitly the formula for the conductance that appears at the beginning of the article. Moreover, it is explained how the density of states is related to the number of Landau occupied levels (which may help to understand the video in the article) and it also contains an explanation, not only on the transverse resistivity but also on the longitudinal one. The notes are based on the book: The physics of low-dimensional semiconductors. J. H. Davies. Cambridge University Press. 1998. It would be a pleasure to contribute to this article and I think the modification will make the article more complete in the sense that it lacks mathematical derivations.  — Preceding unsigned comment added by Anappzz (talk • contribs) 14:16, 18 May 2020 (UTC)
thread_title: Modification of the section Integer Quantum Hall Effect

message: The figure https://en.wikipedia.org/wiki/File:Rhoxy.jpg is a problem:
* wrong caption: there are no inset
* wrong \rho_xy axis: these are normalized values not kOhms
* the \rho_xx axis should just be considered "arbitrary units" for simplicity  — Preceding unsigned comment added by Scharleb (talk • contribs) 01:07, 20 October 2021 (UTC)
thread_title: Error in figure