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Andreev reflection, named after the Russian physicist Alexander F. Andreev, is a type of particle scattering which occurs at interfaces between a superconductor (S) and a normal state material (N). It is a charge-transfer process by which normal current in N is converted to supercurrent in S.
Conversely, the (gapless) electron order present in the normal metal is also carried over to the superconductor in that the superconducting gap is lowered near the interface. The microscopic model describing this behavior in terms of single electron processes is called Andreev reflection. It describes how electrons in one material take on the ...
Diagram of Andreev reflection. An electron meeting the interface between a normal conductor and a superconductor produces a Cooper pair in the superconductor and a retroreflected electron hole in the normal conductor. Legend: "N" = normal conductor, "S" = superconductor, red = electron, green = hole. Arrows indicate the spin band occupied by ...
The table below shows some of the parameters of common superconductors. X:Y means material X doped with element Y, T C is the highest reported transition temperature in kelvins and H C is a critical magnetic field in tesla. "BCS" means whether or not the superconductivity is explained within the BCS theory.
In 1950, the theory of the two types of superconductors was further developed by Lev Landau and Vitaly Ginzburg in their paper on Ginzburg–Landau theory. [5] In their argument, a type-I superconductor had positive free energy of the superconductor-normal metal boundary. Ginzburg and Landau pointed out the possibility of type-II ...
Phase diagram (B, T) of a type I superconductor : if B < B c, the medium is superconducting. T c is the critical temperature of a superconductor when there is no magnetic field. The interior of a bulk superconductor cannot be penetrated by a weak magnetic field, a phenomenon known as the Meissner effect. When the applied magnetic field becomes ...
Assume that superconductor A has Ginzburg–Landau order parameter =, and superconductor B =, which can be interpreted as the wave functions of Cooper pairs in the two superconductors. If the electric potential difference across the junction is V {\displaystyle V} , then the energy difference between the two superconductors is 2 e V ...
Hard superconductors often exhibit hysteresis in magnetization measurements. C. P. Bean postulated for the Shubnikov phase an extraordinary shielding process due to the microscopic structure of the materials. He assumed lossless transport with a critical current density J c (B) (J c (B→0) = const. and J c (B→∞) = 0).