Superconductor Science and Technology Volume 26 Number 12. (2013).
Francesco Mancarella, Alexander V Balatsky, Mats Wallin, Anders Rosengren.
Nordic Institute for Theoretical Physics (NORDITA), Roslagstullsbacken 23, SE-106 91 Stockholm, Sweden and
Department of Theoretical Physics, KTH Royal Institute of Technology, SE-106 91 Stockholm, Sweden and
Theoretical Division, Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, USA and
Address for correspondence: NORDITA, Roslagstullsbacken 23, SE-106 91 Stockholm, Sweden.
Abstract
We discuss the angular momentum blockade in small d-wave superconducting grains in an external field. We find that abrupt changes in the angular momentum state of the condensate, angular momentum blockade, occur as a result of changes in the angular momentum of the condensate in an external magnetic field. The effect represents a direct analogy with the Coulomb blockade. We use the Ginzburg–Landau formalism to illustrate how a magnetic field induces a deviation from the d-wave symmetry which is described by a (dx2−y2 + idxy)-order parameter. We derive the behavior of the volume magnetic susceptibility as a function of the magnetic field, and corresponding magnetization jumps at critical values of the field that should be experimentally observable in superconducting grains.
Additional Information:
To the best of our knowledge, this is the first example ever in which a blockade effect for an observable is produced as a result of the orbital angular momentum quantization.