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TT: Tiefe Temperaturen
TT 11: Superconductivity: Heterostructures, Andreev Scattering, Proximity Effect, Coexistence
TT 11.12: Vortrag
Dienstag, 28. März 2006, 12:30–12:45, HSZ 301
Superconducting surfaces under electric fields — •K. Morawetz1,2, P. Lipavský3, J. Koláček4, and M. Schreiber1 — 1Institute of Physics, Chemnitz University of Technology, 09107 Chemnitz, Germany — 2Max-Planck-Institute for the Physics of Complex Systems, Nöthnitzer Str. 38, 01187 Dresden, Germany — 3Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 12116 Prague 2 — 4Institute of Physics, Academy of Sciences, Cukrovarnická 10, 16253 Prague 6, Czech Republic
A boundary condition for the Ginzburg-Landau wave function at surfaces biased by a strong electric field is derived within the de Gennes approach. This condition provides a simple theory of the field effect on the critical temperature of superconducting layers [1,2]. The electric-field dependent surface energy is calculated which provides an alternative explanation of the Tao effect where one observes a formation of a macroscopic sphere out of superconducting grains due to the electric field. The electrostatic potential above the Abrikosov vortex lattice is calculated as well where we include the surface dipole. We propose an experimental measurement by NMR to access this field which can yield informations about material parameters [3].
[1] P. Lipavský, K. Morawetz, J. Kolacek, Ginzburg-Landau theory of superconducting surfaces under electric fields, PRB in press
[2] K. Morawetz, Electric field dependence of pairing temperature and tunneling, Phys. Rev. B 66, 172508
[3] P. Lipavský, K. Morawetz, J. Kolacek, J. J. Mares, E. H. Brandt, M. Schreiber, Bernoulli potential in type-I and weak type-II supercoductors: III. Electrostatic potential above the vortex lattice Phys. Rev. B 71 (2005) 024526-1-7, II. Surface dipole Phys. Rev. B 70 (2004) 104518-1-7, I. Surface charge Phys. Rev. B 69 (2004) 024524-1-7