Lack of Diamagnetism and the Little-Parks Effect

Research output: Contribution to journalArticle


title = "Lack of Diamagnetism and the Little-Parks Effect",
abstract = "When a superconducting sample is submitted to a sufficiently strong external magnetic field, the superconductivity of the material is lost. In this paper we prove that this effect does not, in general, take place at a unique value of the external magnetic field strength. Indeed, for a sample in the shape of a narrow annulus the set of magnetic field strengths for which the sample is superconducting is not an interval. This is a rigorous justification of the Little-Parks effect. We also show that the same oscillation effect can happen for disc-shaped samples if the external magnetic field is non-uniform. In this case the oscillations can even occur repeatedly along arbitrarily large values of the Ginzburg-Landau parameter kappa. The analysis is based on an understanding of the underlying spectral theory for a magnetic Schrodinger operator. It is shown that the ground state energy of such an operator is not in general a monotone function of the intensity of the field, even in the limit of strong fields.",
author = "Soren Fournais and {Persson Sundqvist}, Mikael",
year = "2015",
doi = "10.1007/s00220-014-2267-7",
language = "English",
volume = "337",
pages = "191--224",
journal = "Communications in Mathematical Physics",
issn = "1432-0916",
publisher = "Springer",
number = "1",