Nanoscale Superconductivity: Potential
At the University of Alberta, Dr Frank Marsiglio is
pushing the limits of nanoscale systems research. His
present research focuses on understanding superconductor
systems and their applicability in nanograin superconductivity.
Historically, superconductivity research has been based
on foundations of grand canonical ensembles generating
approximate results with relative margins of error.
Today, the forward thrust of miniaturization has created
a new challenge in solving the problem of marginal errors,
as current experiments detect the difference between
even and odd numbers of electrons in ultra small superconducting
In response to this problem Marsiglio has reformulated
superconductivity equations providing precise values
with no margin of error. This development enables the
proper description of superconductivity in small nanograins
providing a correct description of surfaces and impurities.
Marsiglios research has also taken into account
the order parameter and spatial dependence. Thus, even
the occurrence of surfaces results in a dramatic change
in the order parameter particularly in the case where
the order parameter has d-wave symmetry.
MACI has played an integral part in this nanoscale
research. Having the ability to solve tens of thousands
of coupled equations is imperative for first-rate results
and developments. As the ability to fabricate small
superconducting nanograins improves, and probes for
observing the effect of superconductivity in these grains
improve in resolution, continued computational
infrastructure is a necessity to enable the theory to
be capable of critically examining fascinating properties
Such formalism is essential to properly describe the
results of surface-sensitive probes of the high temperature
superconductors. The impact of this formalization will
continue to influence STM work and photoemission spectroscopy.
Potential ramifications include miniaturization of superconducting
components, and interfacing with superconducting surfaces
on mixed (superconducting and semiconducting) components.
· K. Beach, R. Gooding, F. Marsiglio. Feedback effects
and the Self-Consistent Thouless Criterion of the Attractive
Hubbard Model, accepted for publication, Phys.
Lett. A, March 2001.
· K. Tanaka and F. Marsiglio. Possible Electronic
Shell Structure of Nanoscale Superconductors, Phys.
Lett. A, 265, 133-138, 2000.
· K. Tanaka and F. Marsiglio. The Anderson
Prescription for Surfaces and Impurities, Phys.
Rev. B, 62, 5345-5348, 2000.
· K. Tanaka and F. Marsiglio. Even-odd and
super-even effects in the attractive Hubbard model,
Phys. Rev. B 60, 3508-3526, 1999.
· K. Tanaka and F. Marsiglio. Anderson's "Theorem"
and Bogoliubov-de Gennes Equations for Surfaces and
Impurities, To be published in Physica C, 6th
International Conference on Materials and Mechanisms
of Superconductivity, Houston, February 2000.