Sn
Nanoparticles.
We
have shown how the superconducting energy gap can be
enhanced by ~60% from its bulk value in superconducting
nanoparticles of Sn which are at the limit of
superconductivity for a zero dimensional system. Though
the occurrence of these ‘shell effects’ which
originates from quantum confinement had been predicted
theoretically, our experiments on single, isolated Sn
nanoparticles by a scanning tunneling microscope show for
the first time in a real system that the superconducting
energy gap is very sensitive on the particle size and
shape and very small changes can cause large oscillations
in its value, leading to huge enhancements.
Nature
Materials 9, 550 (2010)
[article]
highlighted
in
Pb
Nanoparticles
We
reported direct experimental evidence of thermal
fluctuations and the gradual breakdown of
superconductivity in Pb nanoparticles as the size is
reduced. The experimental data was well described by a
theoretical model. Thermal fluctuations give rise to a
finite energy gap or “fluctuation dominated regime”
around Tc.
Our results are a first step to understand quantitatively
the
evolution of superconductivity with particle size and
the role of thermal fluctuations for single small
superconductors.
Phys.
Rev. B. 84, 104525 (2011)
[article]
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