Free electrons at zero kelvin?

[chewchun]

At zero kelvin,are there free electrons?

At zero kelvin,the free electrons should have ZERO energy.But they are able to move under the influence of a electric field?
But when they are attracted towards the positive potential shouldn't they gain K.E? So they are moving at zero kelvin?

 

[Morgoth]

you cannot send fermions at such temperature (they won't ever reach 0 K), just because they are fermions and must obey Pauli's exclusion principle they will have energy from that...

 

[mfb]

Zero temperature just means that all particles reach the lowest-possible states. In terms of fermions, they still have energy compared to the ground-state, but this energy does not contribute to temperature.
Note that this definition does not include any "velocity". You can have a collection of electrons at (close to) zero temperature, moving in one direction in your lab.

 

[ZapperZ]

At zero kelvin,are there free electrons?

At zero kelvin,the free electrons should have ZERO energy.But they are able to move under the influence of a electric field?
But when they are attracted towards the positive potential shouldn't they gain K.E? So they are moving at zero kelvin?

I do not understand your issue here. By definition, free electrons as ... FREE! If they are attracted to a "positive potential", then they are NOT free electrons in the first place!

So are they free, or aren't they? And where are these "free electrons" that you are considering? A metal? A metal's band structure is often calculated at 0 K! So the conduction electrons are in the conduction band at 0 K! They are free to move!

Zz.