Nonlinear σ model for odd-frequency triplet superconductivity in superconductor/ferromagnet structures

J. E. Bunder; K. B. Efetov

doi:10.1103/PhysRevB.70.134522

← Back to search

Nonlinear σ model for odd-frequency triplet superconductivity in superconductor/ferromagnet structures

J. E. Bunder, K. B. Efetov

DOI 10.1103/PhysRevB.70.134522 · Physical Review B

T1

Active bibliographic source — not scientific approval

Bibliographic access preserves source history; it does not approve extracted materials or validate reported claims. Review warnings on each occurrence separately.

Abstract

We consider some properties of odd-frequency triplet superconducting condensates. In order to describe fluctuations we construct a supermatrix σ model for the superconductor/ferromagnet or superconductor/normal-metal structures. We show that an odd frequency triplet superconductor, when in isolation or coupled to a normal metal, generally displays behavior comparable to a superconductor with the usual singlet pairings. However, for spin dependent systems such as the superconductor/ferromagnet the two types of superconductor have quite different behavior. We discuss this difference by considering transformations under which the σ model is invariant. Finally, we calculate the low energy density of states in a ferromagnet coupled to a singlet superconductor. If odd frequency triplet components are induced in the ferromagnet the density of states will decrease relative to the usual bulk solution but will not vanish.