國立成功大學「邁向頂尖大學計畫」
延攬優秀人才工作報告表
NCKU’s “Aim for the Top University Project”
Work Report Form for Distinguished Scholars
□續聘continuation of employment ■離職resignation
100 年 7 月 13 日更新
受聘者姓名
Name of the Employee 涂維元
■男 女 Male Female
聘 期 Period of Employment
From 103 年(y)8 月(m)1 日(d) To 103 年(y)12 月(m)31 日(d) 研究或教學或科技研發與
管理計畫名稱 The project title of research,
teaching, technology development and management
量子輸運及量子反饋控制 計畫主持人
（申請單位主管）
Project Investigator (Head of Department/Center)
張為民
補助延聘編號
Grant Number HUA103-3-2-328
一、研究、教學、科技研發與管理工作全程經過概述。（由受聘人填寫）
Please summarize the entire research, teaching, or science and technology R&D and management work process (To be completed by the employee)
1. Research on spintronic interference devices:
Reference:
Matisse W.Y. Tu, A. Aharony, W. M. Zhang and O. Entin-Wohlman
“Real-time dynamics of spin-dependent transport through a double-quantum-dot Aharonov-Bohm interferometer with spin-orbit interaction.”
Phys. Rev. B 90, 165422 (2014)
I am involved in the research titled above and execute the research plan in detail, including theory analysis, data productions and paper writing.
The result is summarized in what follows:
The spin-resolved nonequilibrium real-time electron transport through a double- quantum-dot (DQD) Aharonov-Bohm (AB) interferometer with spin-orbit interaction (SOI) is explored. The SOI and AB interference in the real-time dynamics of spin transport is expressed by effective magnetic fluxes. Analytical formulas for the time- dependent currents, for initially unpolarized spins, are presented. Inmany cases, there appear spin currents in the electrodes, forwhich the spins in each electrode are polarized along characteristic directions, predetermined by the SOI parameters and by the geometry of the system. Special choices of the system parameters yield steady-state currents in which the spins are fully polarized along these characteristic directions. The time required to reach this steady state depends on the couplings of the DQD to the leads.
The magnitudes of the currents depend strongly on the SOI-induced effective fluxes.
Without the magnetic flux, the spin-polarized current cannot be sustained to the steady states, due to the phase rigidity for this system. For a nondegenerate DQD, transient spin transport can be produced by the sole effects of SOI. We also show that one can extract the spin-resolved currents from measurements of the total charge current.
2. Research on comparisons of theoretical methodologies for quantum states in
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nanoelectronic devices.
I am involved in the research titled above and execute the research plan in detail, including theory analysis, data productions and paper writing.
The targeted paper is still under revision. Present results are summarized in what follows:
We present a general solution of the reduced density operator of open electronic systems under the influences of electron reservoirs. The solution is analytically expressed in the most intuitive many-electron basis of the central electronic system. It is applicable to an arbitrary number of orbitals in the central system initially prepared at any electronic configurations. We introduce two approaches attempting to obtain the reduced density matrices of open electronic systems. One approach is the construction of reduced density matrix elements from expectation values of Heisenberg field operators. The other is via the Feynman-Vernon's influence functional method that directly aims at the reduced density matrix itself. The advantage and disadvantage of the two approaches are manifested. As a demonstration, we apply this general solution to study the full electron configuration dynamics of an artificial molecule subjected to nonequilibrium transport circumstance. We take a close look into the notion of transport through channels identified with certain orbtials in the central junction. We resolve the full probability distributions of various electronic configurations in the transport regimes in real time.
The connection of transport through certain orbtals and the participation on occupying these orbitals are provided.
3. Coordination with other group members
I am also involved in research projects mainly conducted by other members in the group.
This includes the following projects:
(i): Detailed investigation of the relation between the resonant orbitals for transport current and the actual occupations on these orbitals in double-quantum-dot Aharonov- Bohm interferometer through the means of monitoring both the quantum states and transport current.
This is mainly conducted by a master student, Mr. Liu, and I give specific points on the focus of analysis. Part of the result is summarized here.
We have verified the effectiveness of the participation of resonant orbitals by observing its non-vanishing occupations while excluding the participation of other orbitals in transport by observing its vanishing occupations. We will continue to write it into a paper.
(ii):Non-Markov electron localization in quantum transport systems.
I have had active discussions with Dr. Yin for this topic. So far we have figured out several regimes where the non-Markov localization of electrons have significant effects in electron transport current. We will continue to write it into a paper.
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二、研究或教學或科技研發與管理成效評估（由計畫主持人或單位主管填寫）
Please evaluate the performance of research, teaching or science and technology R&D and management Work: ( To be completed by Project Investigator or Head of Department/Center)
Excellent!
(1)是否達到延攬預期目標？
Has the expected goal of recruitment been achieved?
Yes.
(2)研究或教學或科技研發與管理的方法、專業知識及進度如何？
What are the methods, professional knowledge, and progress of the research, teaching, or R&D and management work?
The progress of the research is well-controlled
(3)受延攬人之研究或教學或科技研發與管理成果對該計畫(或貴單位)助益如何？
How have the research, teaching, or R&D and management results of the employed person given benefit to the project (or your unit)?
Very good.
(4)受延攬人於補助期間對貴單位或國內相關學術科技領域助益如何？
How has the employed person, during his or her term of employment, benefited your unit or the relevant domestic academic field?
Very good.
(5)具體工作績效或研究或教學或科技研發與管理成果：
Please describe the specific work performance, or the results of research, teaching, or R&D and management work:
Dr. Tu focused on several research topics during his postdoc period in last 5 months (from August 1, 2014 to December 31, 2014) in associating with the research project
“Quantum Transport and Quantum Feedback Controls” (量子輸運及量子反饋控 制 ). His research performance is outstandingly good. Within 5 months, he completed the investigation of the transient quantum transport on spintronic interference devises. This work has been published in Phys. Rev. B 90, 165422 (2014). Another research topic, the comparison of different methods used in the investigating quantum transport physics has also finished, and the paper is revising.
He also collaborated with several other students and postdocs in my group on couple of other topics on electronic transports in nanostructures, and some preliminary results have also been worked out.
(6)是否續聘受聘人? Will you continue hiring the employed person? □續聘Yes ■不續聘No
The budget for the year of 2015 is not clear yet, so we have no resource to continue to hire him within this project. We are looking for other resources.
※此報告表篇幅以三～四頁為原則。This report form should be limited to 3-4 pages in principle.
※此表格可上延攬優秀人才成果報告繳交說明網頁下載。
This report form can be downloaded in http://scholar.lib.ncku.edu.tw/explain/
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