政大機構典藏-National Chengchi University Institutional Repository(NCCUR):Item 140.119/80609
English  |  正體中文  |  简体中文  |  Post-Print筆數 : 27 |  全文笔数/总笔数 : 90773/120835 (75%)
造访人次 : 25095592      在线人数 : 271
RC Version 6.0 © Powered By DSPACE, MIT. Enhanced by NTU Library IR team.
搜寻范围 查询小技巧:
  • 您可在西文检索词汇前后加上"双引号",以获取较精准的检索结果
  • 若欲以作者姓名搜寻,建议至进阶搜寻限定作者字段,可获得较完整数据
  • 进阶搜寻


    请使用永久网址来引用或连结此文件: http://nccur.lib.nccu.edu.tw/handle/140.119/80609


    题名: Gate-tunable Kondo resistivity and dephasing rate in graphene studied by numerical renormalization group calculations
    作者: Lo, Po-Wei;Guo, Guang-Yu;Anders, Frithjof B.
    郭光宇
    贡献者: 應物所
    日期: 2014-05
    上传时间: 2016-01-15 14:42:41 (UTC+8)
    摘要: Motivated by the recent observation of the Kondo effect in graphene in transport experiments, we investigate the resistivity and dephasing rate in the Kondo regime due to magnetic impurities in graphene with different chemical potentials (μ). The Kondo effect due to either carbon vacancies or magnetic adatoms in graphene is described by the single-orbital pseudogap asymmetric Anderson impurity model which is solved by the accurate numerical renormalization group method. We find that although the Anderson impurity model considered here is a mixed-valence system, it can be driven into either the Kondo [μ > μc (critical value) > 0], mixed-valency [μ ≈ μc), or empty-orbital (μ < μc) regime by a gate voltage, giving rise to characteristic features in resistivity and dephasing rate in each regime. Specifically, in the case of μ < μc, the shapes of the resistivity (dephasing rate) curves for different μ are nearly identical. However, as temperature decreases, they start to increase to their maxima at a lower T/TK, but more rapidly [as (TK/T)3/2] than in normal metals [here, T (TK) denotes the (Kondo) temperature]. As T further decreases, after reaching the maximum, the dephasing rate drops more quickly than in normal metals, behaving as (T/TK)3 instead of (T/TK)2 . Furthermore, the resistivity has a distinct peak above the saturation value near TK. In the case of μ > μc, in contrast, the resistivity curve has an additional broad shoulder above 10TK and the dephasing rate exhibits an interesting shoulder-peak shape. In the narrow boundary region (μ ≈ μc), both the resistivity and dephasing rate curves are similar to the corresponding ones in normal metals. This explains the conventional Kondo-like resistivity from recent experiments on graphene with defects, although the distinct features in the resistivity in the other cases (μ < μc or μ > μc) were not seen in the experiments. The interesting features in the resistivity and dephasing rate are analyzed in terms of the calculated T-dependent spectral function, correlation self-energy, and renormalized impurity level.
    關聯: Physical Review B: Condensed Matter & Materials Physics, 89(19), 195424-1-195424-10
    数据类型: article
    显示于类别:[應用物理研究所 ] 期刊論文

    文件中的档案:

    档案 描述 大小格式浏览次数
    195424-1-195424-10.pdf1022KbAdobe PDF417检视/开启


    在政大典藏中所有的数据项都受到原著作权保护.


    社群 sharing

    著作權政策宣告
    1.本網站之數位內容為國立政治大學所收錄之機構典藏,無償提供學術研究與公眾教育等公益性使用,惟仍請適度,合理使用本網站之內容,以尊重著作權人之權益。商業上之利用,則請先取得著作權人之授權。
    2.本網站之製作,已盡力防止侵害著作權人之權益,如仍發現本網站之數位內容有侵害著作權人權益情事者,請權利人通知本網站維護人員(nccur@nccu.edu.tw),維護人員將立即採取移除該數位著作等補救措施。
    DSpace Software Copyright © 2002-2004  MIT &  Hewlett-Packard  /   Enhanced by   NTU Library IR team Copyright ©   - 回馈