Solid State Physics | electrons | thermal conduction

[heycoa]

Homework Statement

Explain why electrons carry a net energy but not a net current in the case of thermal conduction.

Homework Equations

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The Attempt at a Solution

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Please help me understand this!

 

[Simon Bridge]

Focus on the basics to start with:
What does "thermal conduction" mean in this case?
What would a "net current" involve?

 

[heycoa]

I believe thermal conduction means the transition of thermal heat via the electron gas, and net current would be the obvious: dI/dt

 

[Simon Bridge]

##dI/dt## would be the rate of change of net current. A net current would be ##I=dQ/dt## But what does that mean in terms of the motion of electrons? Why "net" current - why not just "current"?

What does "thermal conduction" mean in terms of the motion of electrons?
Why "net" energy? Why not just say they "carry energy"?

 

[Nickie]

In solid state physics, thermal conduction refers to the transfer of heat energy through a material due to the movement of particles. In this case, the particles responsible for carrying heat energy are the electrons. However, unlike in electrical conduction, where electrons also carry a net electric current, in thermal conduction, electrons only carry a net energy.

This can be explained by the fact that in thermal conduction, electrons are not moving in a particular direction as they do in electrical conduction. Instead, they are moving randomly and colliding with other particles in the material. These collisions result in the transfer of energy from one electron to another, causing a net flow of heat energy through the material.

Furthermore, in thermal conduction, the electrons do not have a preferred direction of movement, as they do in electrical conduction where they are guided by an electric field. Therefore, there is no net movement of electrons in a particular direction, and hence no net current.

In summary, in the case of thermal conduction, electrons carry a net energy due to their random movement and collisions with other particles, but they do not carry a net current as there is no preferred direction of movement.