Browsing by Author "Huang, Wen-Min"

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Carrier-mediated exchange coupling and fermi surface topology
(2008-01-20)
Huang, Wen-Min
;
Lai, Hsin-Hua
;
Chang, Cheng-Hung
;
Lin, Hsiu-Hau
;
物理研究所
We investigate the carrier-mediated exchange coupling between two ferromagnets, sandwiching an intermediate thin layer with Rashba interaction. The effective exchange coupling is obtained by integrating out the itinerant carriers. It turns out that the magnetic trends depend sensitively upon the topology of the Fermi surface. As the topology changes from "wedding cake" to "donut", the mediated exchange goes from the oscillatory Ruderman-Kittel-Kasuya-Yosida to the non-collinear spiral interactions accordingly. It is rather surprising that the Fermi surface topology determines which type of magnetic interaction becomes dominant. Finally, we also discuss potential applications for carrier-mediated exchange coupling across the junction.
Non-collinear magnetic junction mediated by Rashba interaction
(2007-03-01)
Huang, Wen-Min
;
Chang, Cheng-Hung
;
Lin, Hsiu-Hau
;
物理研究所
;
Institute of Physics
We study the non-collinear exchange coupling across the trilayer magnetic junction composed of an intermediate layer with Rashba interaction and two sandwiching ferromagnetic ones. To compute the mediated exchange coupling between the ferromagnetic layers, one needs to go beyond the single-particle argument and numerically integrates over contributions from the whole Fermi surface. We found interesting competition between the oscillatory Ruderman-Kittel-Kasuya-Yosida and the non-collinear spiral interactions. Surprisingly, the Fermi surface topology determines which type of magnetic interaction becomes dominant. Finally, we also discuss potential applications for the non-collinear exchange coupling across the junction. (C) 2006 Elsevier B.V. All rights reserved.
Noncollinear exchange coupling in a trilayer magnetic junction and its connection to Fermi surface topology
(2006-06-01)
Huang, Wen-Min
;
Chang, Cheng-Hung
;
Lin, Hsiu-Hau
;
物理研究所
;
Institute of Physics
We investigate the noncollinear exchange coupling across a trilayer magnetic junction composed of an intermediate layer with Rashba interaction and two sandwiching ferromagnetic layers. To compute the mediated exchange coupling, one needs to go beyond the single-particle argument and integrate over the contributions from the whole Fermi surface. Surprisingly, we find that the topology of the Fermi surface plays a crucial role in determining whether the oscillatory Ruderman-Kittel-Kasuya-Yosida or the spiral interactions will dominate. At the end, we discuss the connection of our numerical results to experiments and potential applications.