Superconducting coherence length

A Superconducting coherence length, usually denoted as $\xi$, can be interpreted in two different ways:

• It gives approximate spatial dimension (size) of the Cooper pair,
• It sets the length scale on which the superconducting order parameter changes considerably.

The superconducting coherence length ($\xi$) is one of two parameters in a Ginzburg-Landau theory of superconductivity.

It is given by:

$\xi ={\sqrt {\frac {\hbar ^{2}}{2m|\alpha |}}}={\frac {2\hbar v_{f}}{\pi E_{g}}}$

See also

• phenomenological Ginzburg-Landau theory of superconductivity
• microscopic BCS theory of superconductivity