The Nature of the Cooper Pair - University of Liverpool
The Nature of the Cooper Pair - University of Liverpool
The Nature of the Cooper Pair - University of Liverpool
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<strong>The</strong> potential energy <strong>of</strong> an electron due to a positive ion is<br />
U = − e2<br />
4πɛ0r .<br />
This is normally cancelled out by <strong>the</strong> free electrons. If an ion is<br />
displaced, <strong>the</strong> change in <strong>the</strong> potential is <strong>the</strong> attractive potential<br />
that now appears. This may be estimated by <strong>the</strong> small change<br />
approximation:<br />
δU ≈ dU<br />
dr δr.<br />
Superconductivity 3