English  |  正體中文  |  简体中文  |  Items with full text/Total items : 74010/74010 (100%)
Visitors : 24681107      Online Users : 232
RC Version 7.0 © Powered By DSPACE, MIT. Enhanced by NTU Library IR team.
Scope Tips:
  • please add "double quotation mark" for query phrases to get precise results
  • please goto advance search for comprehansive author search
  • Adv. Search
    HomeLoginUploadHelpAboutAdminister Goto mobile version

    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/71668

    Title: Anchoring Effect on Spin Transport in Amine-Ended Single-Molecule Magnetic Junctions: A First-Principles Study
    Authors: 林家榮;Lin,Chia-Jung
    Contributors: 物理學系
    Keywords: 單分子接面;自旋電子學;分子電子學;橋接效應;自旋傳輸;Single-Molecule Junctions;Spintronics;Molecular Electronics;Anchoring Effect;Spin Transport
    Date: 2016-07-20
    Issue Date: 2016-10-13 13:29:07 (UTC+8)
    Publisher: 國立中央大學
    Abstract: 近年來,將微小尺寸的分子使用在電子元件中,其特殊的電子傳輸特性使得單分子接面吸引相當多的研究;但是透過磁性金屬作為電極引入自旋極化效果,進而探討單分子磁性接面中的自旋傳輸特性,目前仍然相當缺乏實驗和理論的研究。在實驗上,STM-BJ和MCBJ兩項技術都能成功地建構所謂的單分子通道。但是對於精準度還是有很大的改善空間,所以需要重複這些實驗好幾百次來匯集成長條圖,以便降低實驗之間的差異性。而在理論上,我們已成功的利用第一原理計算方法以及非平衡態格林函數方法來研究單分子接面。足夠的實驗研究告訴我們,在如此微小的尺度,介面的影響力對於單分子通道是非常重要的,像是橋接分子就是其中一個切入點。經驗上,傳統的非磁性單分子通道認為以金作為電極,並以硫(thiol)作為橋接分子,可以得到有效的charge transfer和穩定的鍵結。但對於磁性電極(鈷),哪一個橋接分子才能得到有效的spin transfer?
    ;Two novel disciplines: spintronics and molecular electronics are significant revolutions in electronics applications. A specific topic between these two fields is single-molecule magnetic junction which combines spin effect and molecule devices. To thoroughly understand and control the single-molecule magnetic junction, we focus on the surface effect by replacing the anchoring group. Among different experimental techniques, mechanically controllable break junction (MCBJ) and STM break junction (STM-BJ) are extensively used in investigating the transport properties of single-molecule junction. Based on experimental processes, strain effect is necessarily included by stretching simulation. Moreover, to clarify the anchoring effect, this study considers two different anchoring ions forming two molecules, 1,4-benzenediamine (BDA) and 1,4-benzenedithol (BDT), sandwiched by two Co hcp[0001] nanowires. First-principle calculation with non-equilibrium green’s function gives adequate investigations of strain and anchoring effect on the spin transport properties. These two effects crucially impact on spin transport in single-molecule magnetic junctions. Our research demonstrates that the strain-enhanced spin injection efficiency of amine-ended single-molecule magnetic junction (BDA-based junction) involving a sign reversal and nearly perfect spin injection could be tuned by mechanical control. Besides, comparing BDA- and BDT-based junctions reveals the superior spin transfer in the amine-ended magnetic junctions (Co/Amine-ended/Co) is in sharp contrast to better charge transfer in the thiol-ended non-magnetic junctions (Au/thiol-ended/Au). Our interesting findings may pave a way for promising and potential tunability in spin injection efficiency for amine-ended single-molecule magnetic junction, simply under mechanical stimulus of break junction technique.
    Appears in Collections:[物理研究所] 博碩士論文

    Files in This Item:

    File Description SizeFormat

    All items in NCUIR are protected by copyright, with all rights reserved.

    社群 sharing

    ::: Copyright National Central University. | 國立中央大學圖書館版權所有 | 收藏本站 | 設為首頁 | 最佳瀏覽畫面: 1024*768 | 建站日期:8-24-2009 :::
    DSpace Software Copyright © 2002-2004  MIT &  Hewlett-Packard  /   Enhanced by   NTU Library IR team Copyright ©   - 隱私權政策聲明