Cooper pair transport and macroscopic quantum dynamics in Josephson junctions through ferromagnetic insulators
Artikel i vetenskaplig tidskrift, 2008

We theoretically investigate the cooper pair transport and the macroscopic quantum dynamics of a Josephson junction with a superconductor (S) and a ferromagnetic insulator (FI). By use of the recursive Green's function method, we numerically found the formation of the pi junction in the case of the fully spin-polarized FI. On the other hand, the Josephson current through the spin filtering barrier does not show the pi junction behaviors. By deriving the effective action from microscopic Hamiltonian, a pi junction flux qubit is proposed. In this qubit, a quantum two-level system is spontaneously generated and the effect of the quasiparticle dissipation is found to be very weak.. These features make it possible to realize a quiet qubit with high coherency.

ferromagnetic insulator

computer

spintronics

Green's function method

qubit

Josephson junction

quantum

Författare

Shiro Kawabata

Chalmers, Mikroteknologi och nanovetenskap (MC2)

Y. Asano

Hokkaido University

Y. Tanaka

Nagoya University

S. Kashiwaya

National Institute of Advanced Industrial Science and Technology

A. A. Golubov

University of Twente

Physica C: Superconductivity and its Applications

0921-4534 (ISSN)

Vol. 468 701-704

Ämneskategorier

Den kondenserade materiens fysik

DOI

10.1016/j.physc.2007.11.069