Electrons below the Fermi level do not conduct electricity
the verdict
REFUTED
the evidence says no
refutedsupported
the weight of evidence
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Retrieved physics literature establishes that electrons lying at or just below the Fermi level can readily move through a material when an external electric field is applied, constituting an electric current.
of electrons at all times. Electric current consists of a flow of electrons. In metals there are many electron energy levels near the Fermi level, so
Electrical resistivity (also called volume resistivity or specific electrical resistance) is a fundamental specific property of a material that measures its electrical resistance or how strongly it resists electric current. A low resistivity indicates a material that readily allows electric current. Resistivity is commonly represented by the Greek letter ρ (rho). The SI unit of electrical resistiv
In metals, the Fermi level lies in the conduction band (see Band Theory, above) giving rise to free conduction electrons. However, in semiconductors the position of the Fermi level is within the band gap, about halfway between the conduction band minimum (the bottom of the first band of unfilled electron energy levels) and the valence band maximum (the top of the band below the conduction band, of filled electron energy levels). That applies for intrinsic (undoped) semiconductors. This means that at absolute zero temperature, there would be no free conduction electrons, and the resistance is infinite. However, the resistance decreases as the charge carrier density (i.e., without introducing further complications, the density of electrons) in the conduction band increases. In extrinsic (doped) semiconductors, dopant atoms increase the majority charge carrier concentration by donating electrons to the conduction band or producing holes in the valence band. (A "hole" is a position where an electron is missing; such holes can behave in a similar way to electrons.) For both types of donor or acceptor atoms, increasing dopant density reduces resistance. Hence, highly doped semiconductors behave metallically. At very high temperatures, the contribution of thermally generated carriers dominates over the contribution from dopant atoms, and the resistance decreases exponentially with temperature.
Of all common substances, metals conduct heat and electricity to the greatest extent. They also exhibit very readily a range of more complicated phenomena – the galvanomagnetic, thermomagnetic and thermoelectric effects – which results when an electric field, a thermal gradient and a magnetic field are combined in various ways. Any theory of the metallic state, therefore, must explain why metals should demonstrate these properties as well as they do, and account for the variation of the physical quantities in question with temperature, electric field, atomic structure and so on. It is now well established that the simplest metals are characterised by an energy band structure in which the topmost occupied band is half full, so making it easy to impart extra energy to those electrons lying at or just below the Fermi level. The electrons in this band are loosely bound to the atomic cores, and can readily move through the material. When an external electric field is applied, the average motion of such electrons in the direction of the field constitutes an electric current, while a thermal current results (in the presence of a thermal gradient) from the diffusion of electrons from hot to cold areas. Similar qualitative explanations may be furnished for the more complicated thermal, electric and magnetic effects. Quantitatively, the key to the calculation of the transport coefficients – and the electrical and thermal conductivities, the Hall coefficient, and so on – lies in the eva
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