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In condensed matter physics, the Fermi surface is the surface in reciprocal space which separates occupied electron states from unoccupied electron states at zero temperature. [1] The shape of the Fermi surface is derived from the periodicity and symmetry of the crystalline lattice and from the occupation of electronic energy bands .
The periodicity of these oscillations can be measured, and in turn can be used to determine the cross-sectional area of the Fermi surface. [8] If the axis of the magnetic field is varied at constant magnitude, similar oscillations are observed. The oscillations occur whenever the Landau orbits touch the Fermi surface.
The Fermi level of a solid-state body is the thermodynamic work required to add one electron to the ... as well as which surface is selected (its crystal orientation ...
Luttinger's theorem states that the volume enclosed by a material's Fermi surface is directly proportional to the particle density.. While the theorem is an immediate result of the Pauli exclusion principle in the case of noninteracting particles, it remains true even as interactions between particles are taken into consideration provided that the appropriate definitions of Fermi surface and ...
The Pomeranchuk instability is an instability in the shape of the Fermi surface of a material with interacting fermions, causing Landau’s Fermi liquid theory to break down. It occurs when a Landau parameter in Fermi liquid theory has a sufficiently negative value, causing deformations of the Fermi surface to be energetically favourable.
Within the Brillouin zone, a constant-energy surface represents the loci of all the -points (that is, all the electron momentum values) that have the same energy. Fermi surface is a special constant-energy surface that separates the unfilled orbitals from the filled ones at zero kelvin.
The area in momentum space that remains ungapped is called the Fermi arc. [2] Fermi arcs also appear in some materials with topological properties such as Weyl semimetals where they represent a surface projection of a two dimensional Fermi contour and are terminated onto the projections of the Weyl fermion nodes on the surface.
The Fermi energy surface in reciprocal space is known as the Fermi surface. The nearly free electron model adapts the Fermi gas model to consider the crystal structure of metals and semiconductors , where electrons in a crystal lattice are substituted by Bloch electrons with a corresponding crystal momentum .