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Spin density is electron density applied to free radicals. It is defined as the total electron density of electrons of one spin minus the total electron density of the electrons of the other spin. One of the ways to measure it experimentally is by electron spin resonance, [14] neutron diffraction allows direct mapping of the spin density in 3D ...
The carrier density is important for semiconductors, where it is an important quantity for the process of chemical doping.Using band theory, the electron density, is number of electrons per unit volume in the conduction band.
The density of electrons in the material is simply the integral of the Fermi–Dirac distribution times the density of states: / = () Although there are an infinite number of bands and thus an infinite number of states, there are only a finite number of electrons to place in these bands.
where is the current density, is the external electric field, is the electronic density (number of electrons/volume), is the mean free time and is the electron electric charge. Other quantities that remain the same under the free electron model as under Drude's are the AC susceptibility, the plasma frequency , the magnetoresistance , and the ...
The wave function of fermions, including electrons, is antisymmetric, meaning that it changes sign when two electrons are swapped; that is, ψ(r 1, r 2) = −ψ(r 2, r 1), where the variables r 1 and r 2 correspond to the first and second electrons, respectively. Since the absolute value is not changed by a sign swap, this corresponds to equal ...
In semiconductors with non-simple band structures, this relationship is used to define an effective mass, known as the density of states effective mass of electrons. The name "density of states effective mass" is used since the above expression for N C is derived via the density of states for a parabolic band.
When the density of electrons is not in equilibrium, diffusion of electrons will occur. For example, when a bias is applied to two ends of a chunk of semiconductor, or a light is shining in one place (see right figure), electrons will diffuse from high density regions (center) to low density regions (two ends), forming a gradient of electron ...
In electromagnetism, charge density is the amount of electric charge per unit length, surface area, or volume. Volume charge density (symbolized by the Greek letter ρ) is the quantity of charge per unit volume, measured in the SI system in coulombs per cubic meter (C⋅m −3), at any point in a volume.