What is Spin Hall effect and quantum hall effect

[yashar]

hi
what is Spin Hall effect and quantum hall effect?
i can not find a good description on wikipedia.com do you have a good link or description?
and another question: why in franck hertz experiment we use MERCURY instead of hydrogen?
thanks

 

[pseudophonist]

The quantum hall effect is due to the quantisation of magnetic flux passing through the sample. The area occupied by the flux quantum is dependent on field and temperature. This quantisation of flux is related to the Shubnikov De-Haas and De-Haas Von-Alpen effects which have reasonably good descriptions on wikipedia. There are lolads of good books on the subject too, with good mathematical models for each effect as well

With regards to the Franck-Herz experiment, there are two possibilities which i can think of: Mercury vapour is easier to obtain in a pure form (since mercury liquid has a high vapour pressure and is liquid at room temperature)
or
Mercury has a lower excitation energy (check this!)