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 dependant 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!)

 

[Entropia]

The Spin Hall effect is a phenomenon in which an electric current induces a spin polarization in a material, resulting in a separation of spin-up and spin-down electrons. This effect is due to the spin-orbit coupling, which is the interaction between the spin of an electron and its motion. The quantum Hall effect, on the other hand, is a phenomenon that occurs in a two-dimensional electron gas subjected to a strong magnetic field, where the electrons can only move along the edges of the material. This results in quantized Hall conductance, or the measurement of electrical current in response to an applied electric field.

As for your question about the Franck-Hertz experiment, mercury is used because it has a low ionization energy, making it easier for the electrons to be excited and undergo collisions with the mercury atoms. This allows for a clear and distinct pattern in the energy levels of the electrons, making it easier to observe and measure. Hydrogen, on the other hand, has a higher ionization energy and is not as easily excited, making it more difficult to observe the energy levels.