Electric conduction in metals
• Microscopic representation of a copper wire: a network of ions and a large number of electrons (density of the order of n ≈ 1023 cm−3) shared in the network. These electrons can carry an electric current.
• Drude model: three hypotheses,
1. The electrons undergo instantaneous collisions (mainly with the thermal vibrations of the lattice),
2. Between two collisions, no interaction with the network,
3. Thermal agitation which intensifies with T.
Fondamental : Movement of electrons within a metal
Under an electric field, in steady state (t ≫ τ, where τ is the average time between two collisions), a group of electrons (n ≈ 10 23 cm −3) moves at a constant speed.
