Free Electron Theory
The electron theory of materials is to explain the structure and properties
of solids through their electronic structure. It also gives information about
bonding in solids, energy levels in metals and cohesive & repulsive forces
in metals.
Development of Free Electron Theory
➢ The Classical free electron theory
[Drude and Lorentz]
It is a macroscopic theory, through which free electrons in lattice
and it obeys the laws of classical mechanics. Here the electrons are
assumed to move in a constant potential.
➢ The Quantum free electron theory
[Sommerfeld Theory]
It is a microscopic theory, according to this theory the electrons in
lattice moves in a constant potential and it obeys law of quantum
mechanics.
➢ Brillouin Zone Theory
[Band Theory]
Bloch developed this theory in which the electrons move in a
periodic potential provided by periodicity of crystal lattice. It
explains the mechanisms of conductivity, semi conductivity on the
basis of energy bands and hence band theory.
➢ Drude Theory
This theory initially proposed by Drude in 1900, and it’s the first
theory to explain the electrical conduction in conducting materials
and reveals that free electrons are responsible for the electrical
conduction.
The electron theory of materials is to explain the structure and properties
of solids through their electronic structure. It also gives information about
bonding in solids, energy levels in metals and cohesive & repulsive forces
in metals.
Development of Free Electron Theory
➢ The Classical free electron theory
[Drude and Lorentz]
It is a macroscopic theory, through which free electrons in lattice
and it obeys the laws of classical mechanics. Here the electrons are
assumed to move in a constant potential.
➢ The Quantum free electron theory
[Sommerfeld Theory]
It is a microscopic theory, according to this theory the electrons in
lattice moves in a constant potential and it obeys law of quantum
mechanics.
➢ Brillouin Zone Theory
[Band Theory]
Bloch developed this theory in which the electrons move in a
periodic potential provided by periodicity of crystal lattice. It
explains the mechanisms of conductivity, semi conductivity on the
basis of energy bands and hence band theory.
➢ Drude Theory
This theory initially proposed by Drude in 1900, and it’s the first
theory to explain the electrical conduction in conducting materials
and reveals that free electrons are responsible for the electrical
conduction.
