Y. Takane, ENHANCEMENT OF CONDUCTANCE FLUCTUATIONS IN NORMAL METALS SANDWICHED BETWEEN SUPERCONDUCTORS, Journal of the Physical Society of Japan, 63(8), 1994, pp. 2849-2852
Conductance fluctuations in superconductor-normal metal-superconductor
junctions are studied at zero temperature. It is shown that the ampli
tude of the fluctuations is no longer characterized by the universal v
alue, of order of e2/h, but generally depends on the sample size and t
he phase relaxation length L(phi). In the particular cases where the s
ample size is much smaller than Lphi, we find that an enhancement of t
he fluctuations greater than the order of e2/h can be expected to aris
e. It is ascribed to a manifestation of the large fluctuation in the l
evel density, which is caused by confinement of quasiparticles in the
normal-metal region due to Andreev reflection.