Probing the exchange field of a quantum-dot spin valve by a superconducting lead

Björn Sothmann; David Futterer; Michele Governale; Jürgen König

doi:10.1103/PhysRevB.82.094514

← Back to search

Probing the exchange field of a quantum-dot spin valve by a superconducting lead

Björn Sothmann, David Futterer, Michele Governale, Jürgen König

DOI 10.1103/PhysRevB.82.094514 · 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

Electrons in a quantum-dot spin valve, consisting of a single-level quantum dot coupled to two ferromagnetic leads with magnetizations pointing in arbitrary directions, experience an exchange field that is induced on the dot by the interplay of Coulomb interaction and quantum fluctuations. We show that a third, superconducting lead with large superconducting gap attached to the dot probes this exchange field very sensitively. In particular, we find striking signatures of the exchange field in the symmetric component of the supercurrent with respect to the bias voltage applied between the ferromagnets already for small values of the ferromagnets’ spin polarization.