發(fā)布時間：2018-07-03 12:05

  本文選題：介觀系統(tǒng) + 量子器件　； 參考：《湖南大學(xué)》2015年碩士論文

【摘要】：隨著新興技術(shù)的發(fā)展,越來越多的納米量子器件已經(jīng)被研發(fā)出來。由于體系的輸運(yùn)性質(zhì)決定了器件的特性,因而輸運(yùn)性質(zhì)的研究具有重要的理論研究意義和潛在的應(yīng)用價(jià)值。目前介觀體系的量子自旋輸運(yùn)研究是凝聚態(tài)物理中十分活躍的前沿研究領(lǐng)域之一。它不但揭示出一系列重要的物理內(nèi)稟,同時也呈現(xiàn)出廣闊的應(yīng)用前景。本論文的研究內(nèi)容圍繞量子點(diǎn)體系內(nèi)的自旋輸運(yùn)性質(zhì)進(jìn)行,主要包括如下四個方面,細(xì)節(jié)如下:第一章:介紹了介觀體系的研究背景及現(xiàn)狀,量子器件的發(fā)展,自旋電子器件及其應(yīng)用,介觀尺度下特別是量子點(diǎn)體系中的自旋極化輸運(yùn)性質(zhì)。簡單介紹了處理介觀體系輸運(yùn)問題時人們主要采用的幾種方案。第二章:介紹了一些介觀體系輸運(yùn)研究用到的基本理論,主要介紹了Buttiker散射矩陣?yán)碚?非平衡態(tài)格林函數(shù)方法,Master方程。并且簡單介紹了這些基本定義和理論在量子點(diǎn)體系中的運(yùn)用。第三章:為了在自旋電子器件中實(shí)現(xiàn)有效的自旋注入,完全極化流或純自旋流(即不帶有電荷流)作為有效的方法被廣泛地研究。近年來,三端自旋器件被廣泛地用來產(chǎn)生完全極化流或純自旋流。我們采用非平衡態(tài)格林函數(shù)方法,研究了一個鐵磁(FM)端和兩個非磁性半導(dǎo)體(SC)端與一個量子點(diǎn)耦合組成的一個三端量子點(diǎn)體系的自旋輸運(yùn)性質(zhì)。結(jié)果顯示當(dāng)調(diào)節(jié)某一非磁性半導(dǎo)體端的外部電壓在一個合適的范圍,在另一個非磁性半導(dǎo)體端會出現(xiàn)純自旋流平臺和完全極化流平臺,并且在一個大的外部電壓變化范圍內(nèi)平臺都不會消失。第四章:我們還進(jìn)一步從理論上研究了一些參數(shù)包括溫度tkB,門電壓控制的量子點(diǎn)能級0?和其它端的端電壓對純自旋電子流平臺和完全極化流平臺的影響。我們發(fā)現(xiàn)參數(shù)的變化對SC1端的純自旋電子流平臺和完全極化流平臺有相當(dāng)大的影響。因?yàn)檫@些參數(shù)的變化往往不可避免,所以我們進(jìn)而研究了這些參數(shù)的變化對純自旋流平臺的影響的補(bǔ)償。我們通過調(diào)節(jié)其它參數(shù)值來抵消某一個參數(shù)的變化對產(chǎn)生純自旋流平臺帶來的影響。此外,為了讓我們的研究結(jié)果更具普遍性,我們采用了不同的器件參數(shù)且也得到了類似的結(jié)論。最后對本論文的工作進(jìn)行了總結(jié)。
[Abstract]:With the development of new technology, more and more nano quantum devices have been developed. Because the transport properties of the system determine the characteristics of the devices, the study of transport properties has important theoretical research significance and potential application value. The study of quantum self rotation transport in mesoscopic system is very active in condensed matter physics One of the frontier research fields. It not only reveals a series of important physical intrinsic endowments, but also presents a broad application prospect. The research content of this thesis focuses on the spin transport properties in the quantum dot system, including the following four aspects, the details are as follows: Chapter 1: the research background and status of mesoscopic system, quantum The development of devices, spintronic devices and their applications, the spin polarization transport properties of the mesoscopic scale systems, especially in quantum dots, are introduced briefly. In the second chapter, the basic theories used in the transport study of mesoscopic systems are introduced, and the Buttiker scattering is mainly introduced. Matrix theory, nonequilibrium Green function method and Master equation. And the application of these basic definitions and theories in quantum dot system is briefly introduced. The third chapter is that in order to achieve effective spin injection in spintronic devices, full polarization flow or pure spin flow (i.e. without charge flow) is widely studied as an effective method. In recent years, three terminal spin devices have been widely used to produce complete polarization flow or pure spin flow. We have studied the spin transport properties of a three terminal quantum dot system consisting of a ferromagnetic (FM) end and two nonmagnetic semiconductor (SC) ends coupled with a quantum dot using the nonequilibrium Green function method. The external voltage of the nonmagnetic semiconductor end is in a suitable range, and there will be a pure spin flow platform and a fully polarized flow platform at the other non magnetic semiconductor end, and the platform will not disappear in a large external voltage range. Fourth chapter: we further theoretically study some parameters including the temperature tkB, the gate power. The effect of the pressure controlled quantum point energy level 0? And the end voltage of other ends on the pure spintronic flow platform and the fully polarized flow platform. We found that the changes in the parameters have considerable influence on the pure spintronic and fully polarized flow platforms at the SC1 end. Because these parameters are inevitable, we have further studied this Some parameters are compensated for the effect of the pure spin flow platform. We counteract the effect of the change of one parameter on the pure spin flow platform by adjusting the other parameter values. In addition, in order to make our results more universal, we have adopted different device parameters and obtained similar conclusions. The work of the paper is summarized.
【學(xué)位授予單位】：湖南大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：O471.1

【參考文獻(xiàn)】

相關(guān)期刊論文 前4條

1 陳明倫;梁敢;曹艷華;王禮勝;勾慶東;劉宇安;周運(yùn)志;;電子通過量子點(diǎn)輸運(yùn)的微分電導(dǎo)[J];原子與分子物理學(xué)報(bào);2014年01期

2 羅浩平;王虹麟;;量子電子器件及其應(yīng)用[J];電子與封裝;2008年12期

3 翁壽松;量子效應(yīng)器件正在崛起[J];電子與封裝;2005年07期

4 張吉英,馮秋菊,呂有明,范希武,申德振;自旋電子學(xué)及其器件應(yīng)用[J];光機(jī)電信息;2004年09期

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本文編號：2093575