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  2. Density of states - Wikipedia

    en.wikipedia.org/wiki/Density_of_states

    The density of states related to volume V and N countable energy levels is defined as: = = (()). Because the smallest allowed change of momentum for a particle in a box of dimension and length is () = (/), the volume-related density of states for continuous energy levels is obtained in the limit as ():= (()), Here, is the spatial dimension of the considered system and the wave vector.

  3. Effective mass (solid-state physics) - Wikipedia

    en.wikipedia.org/wiki/Effective_mass_(solid...

    In solid state physics, a particle's effective mass (often denoted ) is the mass that it seems to have when responding to forces, or the mass that it seems to have when interacting with other identical particles in a thermal distribution. One of the results from the band theory of solids is that the movement of particles in a periodic potential ...

  4. Electronic band structure - Wikipedia

    en.wikipedia.org/wiki/Electronic_band_structure

    The density of states function g(E) is defined as the number of electronic states per unit volume, per unit energy, for electron energies near E. The density of states function is important for calculations of effects based on band theory.

  5. BCS theory - Wikipedia

    en.wikipedia.org/wiki/BCS_theory

    This energy gap is highest at low temperatures but vanishes at the transition temperature when superconductivity ceases to exist. The BCS theory gives an expression that shows how the gap grows with the strength of the attractive interaction and the (normal phase) single particle density of states at the Fermi level. Furthermore, it describes ...

  6. Urbach energy - Wikipedia

    en.wikipedia.org/wiki/Urbach_energy

    The Urbach Energy, or Urbach Edge, is a parameter typically denoted , with dimensions of energy, used to quantify energetic disorder in the band edges of a semiconductor. It is evaluated by fitting the absorption coefficient as a function of energy to an exponential function. It is often used to describe electron transport in structurally ...

  7. Empty lattice approximation - Wikipedia

    en.wikipedia.org/wiki/Empty_lattice_approximation

    The empty lattice approximation is a theoretical electronic band structure model in which the potential is periodic and weak (close to constant). One may also consider an empty [clarification needed] irregular lattice, in which the potential is not even periodic. [1] The empty lattice approximation describes a number of properties of energy ...

  8. Fermi–Dirac statistics - Wikipedia

    en.wikipedia.org/wiki/Fermi–Dirac_statistics

    Scientists. v. t. e. Fermi–Dirac statistics is a type of quantum statistics that applies to the physics of a system consisting of many non-interacting, identical particles that obey the Pauli exclusion principle. A result is the Fermi–Dirac distribution of particles over energy states. It is named after Enrico Fermi and Paul Dirac, each of ...

  9. Planck's law - Wikipedia

    en.wikipedia.org/wiki/Planck's_law

    Planck's law accurately describes black-body radiation. Shown here are a family of curves for different temperatures. The classical (black) curve diverges from observed intensity at high frequencies (short wavelengths). Formula in cgs units. In physics, Planck's law (also Planck radiation law[1]: 1305 ) describes the spectral density of ...