Mod-02 Lec-26 Electronic Contribution to Specific Heat at Constant Volume

[@shattique4785]

Thank you Professor Haridoss. You have helped me to connect the dots. Really appreciate your teaching.

[@mfoucault1984]

If you want to be a little subtle in the derivation of the electronic C_V, why don't u use the sommerfeld expansion? You are using a classic energy given by the equipartition theorem, that is the energy 'gained' by each electron, mainly 3/2 k_B T but you are counting electrons considering a quantum mechanics probability distribution (F-D).

[@lokaiahbapathi3913]

At T=0K, the Number of states below the Fermi Level will be equal to the total number of electrons(bound + free electrons) available in the system at any instant. A'm I right?

[@lokaiahbapathi3913]

In metals...At T=OK, All the states below the Fermi Level (Ef) are completely filled.. So all these electrons below Ef are bound electrons (not free electrons )... Only Electrons above Fermi Level at any temperature can be considered as Free electrons... Am I right?

[@rocko5461]

www.quora.com/Why-are-there-free-electrons-in-metals

[@rocko5461]

Watch his fifth lecture about free electron gas and also the lectures about confinement and quantization. The free electrons are not truly free electrons as they are still within the extent of the system. They are just delocalized electrons within the lattice. The truly free electron would have a Zero potential. For example in photoelectric effect where the electrons completely escape out. So, in metals, the metallic bond occurs due to electrostatic force between the conduction electrons (delocalized electrons) and positively charged metal ions.

[@preranadash9640]

@Lokaiah Bapathi At T=0k , deep inside the Fermi level electrons are bound but electrons which are occupying states close to Fermi levels (as prof. said within kbT of Fermi energy),can gain energy and move to the higher energy levels which were empty before, are called free electrons. Hope this will help u:)

[@mfoucault1984]

If he is talking about nearly free electrons that are the ones who contribute to the electronic C_V, it is an unfortunate choice to pick 'a' as the width of the well since in the last lecture he took the width of the material as being of length 'L'. Then in minute 6:35 he takes the cube of a being the volume.. somewhat confusing, but are just details.. lectures are great.

[@mfoucault1984]

he explicitly says that 'a' is the extent of the system, maybe that solves it all, i leave this comment for future reference. My bad..