Spectrum of Andreev bound states in Josephson junctions with a ferromagnetic insulator

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:324

Article; Proceedings Paper

Kawabata, Shiro^1,2  Tanaka, Yukio³  Golubov, Alexander A.⁴  Vasenko, Andrey S.⁵  Asano, Yasuhiro⁶ 

[1] Natl Inst Adv Ind Sci & Technol, Nanosyst Res Inst NRI, Tsukuba, Ibaraki 3058568, Japan

[2] Japan Sci & Technol Corp JST, CREST, Kawaguchi, Saitama 3320012, Japan

[3] Nagoya Univ, Dept Appl Phys, Nagoya, Aichi 4648603, Japan

[4] Univ Twente, Fac Sci & Technol, NL-7500 AE Enschede, Netherlands

[5] Inst Max Von Laue Paul Langevin, F-38042 Grenoble, France

[6] Hokkaido Univ, Dept Appl Phys, Sapporo, Hokkaido 0608628, Japan

关键词: Josephson junction;    Spintronics;    Ferromagnetic insulator;    Quantum bit;    Andreev bound state;    Tight binding model;   

DOI  :  10.1016/j.jmmm.2012.02.067

来源: Elsevier

【 摘 要 】

Ferromagnetic-insulator (FI) based Josephson junctions are promising candidates for a coherent superconducting quantum bit as well as a classical superconducting logic circuit. Recently the appearance of an intriguing atomic-scale 0-pi transition has been theoretically predicted. In order to uncover the mechanism of this phenomena, we numerically calculate the spectrum of Andreev bound states in a FI barrier by diagonalizing the Bogoliubov-de Gennes equation. We show that Andreev spectrum drastically depends on the parity of the FI-layer number L and accordingly the pi(0) state is always more stable than the 0 (pi) state if L is odd (even). (C) 2012 Elsevier B.V. All rights reserved.

【 授权许可】

Free