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The problem is that light has almost no momentum to give to the electrons in the solid (one usually makes the assupmtion of $k=0$). The dispersion relation for light is extremely steep because of the light speed ($E=ck$). So the electron has to get (or give) some momentum to make the indirect transition. This is typically achieved through interactions with ...


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If you refer to a layered structure along growth direction (e.g. quantum well, superlattice), you can calculate your mass for different states and positions from the 2nd derivative of the wavefunctions. Perpendicular to it you would have the dispersion (and therefore mass) of a free particle, since you would usually assume that your layer planes are ...


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At present, there is a belief (though obviously not verifiable) by solid-state physicists that a metal cannot exist at absolute zero. The Fermi surface of the metal will be unstable to order of some sort such as superconductivity, charge density waves, magnetic ordering, etc. With that said, let us concentrate on your scenario though. If there are no ...


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In a metal the Fermi energy is somewhere in an unfilled band. At any temperature above absolute zero (which you can never reach) there are states available for electrons to get to and result in conduction at the Fermi surface. This will occur in any metal. Superconductivity is a separate phenomena that I won't touch on here.


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After going through number of articles for temperature reaching absolute zero, I find that it is difficult to attain absolute zero, which may mean that it is very difficult to stop interatomic movements or energy exchanges, and thus absolute zero is near theroretical. As far as superconductivity is concerned it must be a critical point, minimum energy ...


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Have you heard of superconductivity? This is a phenomenon where a material exhibits zero resistivity near absolute zero: it clearly contradicts your assertion that thermal excitation is needed for conductivity near absolute zero. For a semiconductor, it is true that electrons need to be kicked into the conduction band by thermal fluctuations - but for a ...



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