Matthiessensche rule

The Matthiessensche rule (named after Augustus Matthiessen ) is a connection from material science . It generally states that the specific resistance for several independent scattering processes is made up of the sum of the specific resistances of the individual scattering processes: ${\displaystyle \rho }$

${\displaystyle \rho \ =\ \rho _{1}+\rho _{2}}$

For example, the specific resistance is made of a metal composed of a temperature-dependent term which by scattering of the electrons in the lattice vibrations ( phonons ) is created, another temperature-dependent term which by electron-electron scattering occurs, and a temperature un -dependent term, which by Scattering of the electrons at lattice defects occurs. So it applies ${\displaystyle \rho }$

${\displaystyle \rho (T)\ =\ \rho _{\mathrm {Phononen} }(T)+\rho _{\mathrm {Elektronen-Elektronen} }(T)+\rho _{\mathrm {Defekte} }}$,

where the temperature, and as well as are the contributions of the phonons, electron-electron scattering and the defects to the specific resistance. ${\displaystyle T}$ ${\displaystyle \rho _{\mathrm {Phononen} }}$ ${\displaystyle \rho _{\mathrm {Elektronen-Elektronen} }}$ ${\displaystyle \rho _{\mathrm {Defekte} }}$

At room temperature (300 K), the specific resistance is mainly caused by collisions with lattice phonons; near absolute temperature zero (4 K), collisions with foreign atoms and mechanical lattice defects are more relevant. This empirically found rule only applies approximately and not for different single crystals (such as tungsten- doped molybdenum single crystals ).

See also

Electron mobility

literature

• Neil W. Ashcroft, N. David Mermin: Solid State Physics . Saunders College Publishing, New York 1976, ISBN 0-03-083993-9 , pp. 323-324 .

Individual evidence

1. ↑ Wissenschaft-Online Lexika: Entry for "Matthiessensche rule" in the Lexikon der Physik. Retrieved March 9, 2011.