2: Define Fermi surface. Explain the conductivity in metals based on t

1.	2: Define Fermi surface. Explain the conductivity in metals based on themotion of Fermi surface.
Answer» Fermi surface, incondensed-matter physics, abstract interface that defines the allowable energies ofelectronsin a solid. It is well known that in general conductivity of metals increases with decreasing temperature. Although thereare less electrons that are thermally excited above the Fermi energy to contribute to conduction, the decrease in thermal vibrations that scatters conducting electrons has a larger effect, thus conductivity increases. Similarly, electrical conductivity of semiconductors increases with increased temperature because there is more thermal energy to excite a greater number of electrons from the valence band to the conduction band. However, as more electrons populate the conduction band the influence of thermal scattering becomes dominant and conductivity begins to decrease like in a metal.

2: Define Fermi surface. Explain the conductivity in metals based on themotion of Fermi surface.

Answer»

Fermi surface, incondensed-matter physics, abstract interface that defines the allowable energies ofelectronsin a solid.

It is well known that in general conductivity of metals increases with decreasing temperature. Although thereare less electrons that are thermally excited above the Fermi energy to contribute to conduction, the decrease in thermal vibrations that scatters conducting electrons has a larger effect, thus conductivity increases.

Similarly, electrical conductivity of semiconductors increases with increased temperature because there is more thermal energy to excite a greater number of electrons from the valence band to the conduction band. However, as more electrons populate the conduction band the influence of thermal scattering becomes dominant and conductivity begins to decrease like in a metal.

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