Question

The actual energy gap at 0 K in lead is 2.73x10³ eV.
(a) What is the prediction of the BCS theory for this energy gap?

(b) Radiation of what minimum frequency could break apart Cooper pairs in lead at 0 K? In what part of the em spectrum is such radiation?

Answer 1

(a) We know that according to BCS theory, the superconducting energy band gap is given as,

Since the critical temperature of Lead is 7.193 K, we calculate the predicted by BCS theory to be,

(b) To break the Cooper pairs, we need energy equal to the actual superconducting energy gap which is

We know, for radiation. So we get frequency to be,

This frequency lies in Infrared region of spectrum.