Fermi surface

Fermi surface

      in solid-state physics, abstract interface that defines the allowable energies of electrons (electron) in a solid. Named for Enrico Fermi (Fermi, Enrico), who along with P.A.M. Dirac (Dirac, P.A.M.) developed the statistical theory of electrons, the Fermi surface is important for characterizing and predicting the thermal, electrical, magnetic, and optical properties of crystalline metals and semiconductors. It is closely related to the atomic lattice, which is the underlying feature of all crystalline solids, and to electron energy band theory in such materials.

      According to the theory, electrons in a solid lie within valence bands or conduction bands, where they are respectively bound into position or free to move. Each electron has a specific momentum and energy within a band. However, at absolute zero (−273.15 °C, or −459.67 °F), the energy may not exceed a value called the Fermi energy, which therefore divides allowed electronic states of momentum and energy from those that cannot be occupied. In an abstract three-dimensional space where the coordinate axes are the components of momentum, this condition defines a volume whose surface—the Fermi surface—separates occupied states within the volume from empty ones without it.

      The shape of the Fermi surface reflects the arrangement of atoms within a solid and is thus a guide to the properties of the material. In some metals, such as sodium and lithium, the Fermi surface is more or less spherical (a Fermi sphere), which indicates that the electrons behave similarly for any direction of motion. Other materials have Fermi surfaces that resemble American footballs or take on more-intricate shapes, typically with large bumps and depressions. In every case the dynamic behaviour of electrons residing at or near the Fermi surface is crucial in determining electrical, magnetic, and other properties and how they depend on direction within the crystal.

* * *


Universalium. 2010.

Игры ⚽ Поможем написать курсовую

Look at other dictionaries:

  • Fermi surface — In condensed matter physics, the Fermi surface is an abstract boundary useful for predicting the thermal, electrical, magnetic, and optical properties of metals, semimetals, and doped semiconductors. The shape of the Fermi surface is derived from …   Wikipedia

  • Fermi surface — Fermio paviršius statusas T sritis fizika atitikmenys: angl. Fermi surface vok. Fermi Oberfläche, f rus. поверхность Ферми, f pranc. surface de Fermi, f …   Fizikos terminų žodynas

  • Fermi surface — Fermio paviršius statusas T sritis chemija apibrėžtis Vienodos energijos paviršius, ribojantis elektronų užimtas būsenas judesio kiekių erdvėje. atitikmenys: angl. Fermi surface rus. поверхность Ферми …   Chemijos terminų aiškinamasis žodynas

  • Fermi surface of superconducting cuprates — The electronic structure of superconducting cuprates, also called high temperature superconductors (HTSC), is highly anisotropic. First, the cuprates are almost two dimensional (2D): the conducting electrons are manly localized in the CuO2 layers …   Wikipedia

  • fermi surface — noun Usage: usually capitalized F : a theoretical geometric surface that consists of points representing the wavelength and direction of propagation of electrons with energies at the Fermi level in an atom of a solid material, that reflects the… …   Useful english dictionary

  • Fermi surface — Смотри Ферми поверхность …   Энциклопедический словарь по металлургии

  • Fermi liquid — is a generic term for a quantum mechanical liquid of fermions that arises under certain physical conditions when the temperature is sufficiently low. The interaction between the particles of the many body system does not need to be small (see e.g …   Wikipedia

  • Fermi energy — The Fermi energy is a concept in quantum mechanics usually referring to the energy of the highest occupied quantum state in a system of fermions at absolute zero temperature. This article requires a basic knowledge of quantum mechanics.Note that… …   Wikipedia

  • Fermi gas — A Fermi gas, or Free electron gas, is a collection of non interacting fermions. It is the quantum mechanical version of an ideal gas, for the case of fermionic particles. Electrons in metals and semiconductors and neutrons in a neutron star can… …   Wikipedia

  • Fermi point — The term Fermi point has two applications but refers to the same phenomena (special relativity): [ [http://www.physics.wustl.edu/ visser/Analog/talks.html#volovik Effective gravity and quantum field theory in superfluids] ] *Fermi point (Quantum… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”