Ginzburg-Landau theory of vortices in a multi-gap superconductor

A. Brinkman; A. Gurevich; A. Gurevich; A. Nakai; A.A. Golubov; A.A. Golubov; A.A. Golubov; A.E. Koshelev; A.I. Ivanovskii; A.J. Leggett; A.Y. Liu; B.T. Geilikman; C.-R. Hu; F. Bouquet; F. Bouquet; F. Giubileo; G. Dresselhaus; G. Lasher; H. Doh; H. Schmidt; H. Suhl; H.D. Yang; H.J. Choi; I.I. Mazin; I.I. Mazin; I.N. Askerzade; J. Kortus; J. Nagamatsu; J.J. Betouras; J.K. Burdett; J.M. An; K. Park; K. Takanaka; K. Takanaka; K.D. Belashchenko; L. Lyard; L.P. Gor’kov; M. Angst; M. E. Zhitomirsky; M. Iavarone; M. Imada; M. Zehetmayer; M.R. Eskildsen; N. Nakai; P. Miranovic; P. Szabo; P.C. Canfield; R. Cubitt; R. Cubitt; T. Dahm; T. Mishonov; V.-H. Dao; V.A. Moskalenko; Y. De Wilde; Y. Kong; Y. Wang

research

Ginzburg-Landau theory of vortices in a multi-gap superconductor

Abstract

The Ginzburg-Landau functional for a two-gap superconductor is derived within the weak-coupling BCS model. The two-gap Ginzburg-Landau theory is, then, applied to investigate various magnetic properties of MgB2 including an upturn temperature dependence of the transverse upper critical field and a core structure of an isolated vortex. Orientation of vortex lattice relative to crystallographic axes is studied for magnetic fields parallel to the c-axis. A peculiar 30-degree rotation of the vortex lattice with increasing strength of an applied field observed by neutron scattering is attributed to the multi-gap nature of superconductivity in MgB2.Comment: 11 page