本文選題：輪烯分子 + 磁性電極　； 參考：《太原理工大學(xué)》2017年碩士論文

【摘要】：隨著電子學(xué)和電子器件微型化的不斷發(fā)展,人們利用單分子或團(tuán)簇,例如有機(jī)小分子和生物分子等構(gòu)建各種功能的電子元器件已經(jīng)成為當(dāng)今的發(fā)展趨勢(shì)。同時(shí)研究和測(cè)量這些分子器件的電學(xué)特性或光學(xué)特性也逐漸發(fā)展成為了一門獨(dú)立的學(xué)科,即分子電子學(xué)。隨著測(cè)量手段的不斷發(fā)展和完善,分子電子學(xué)在實(shí)驗(yàn)和理論上都取得了實(shí)質(zhì)性的進(jìn)展。正是由于電輸運(yùn)性質(zhì)對(duì)分子器件的性能起著至關(guān)重要的作用,因此研究分子器件的電輸運(yùn)機(jī)制具有非常重要的意義。有機(jī)分子由于其較弱的自旋軌道耦合效應(yīng)和超精細(xì)相互作用被認(rèn)為是構(gòu)造分子器件最熱門的材料之一。其中1,6-亞甲基[10]輪烯分子就是一種很有發(fā)展前景的有機(jī)分子,它擁有獨(dú)特的幾何結(jié)構(gòu)和奇特的電子性質(zhì)。該分子因?yàn)槠浞�(wěn)定的π共軛電子結(jié)構(gòu)和顯著的芳香特性而備受關(guān)注,它也是實(shí)驗(yàn)研究的理想對(duì)象。但是到目前為止,對(duì)于該分子的電輸運(yùn)理論還少有研究。在本論文中,使用鐵、鈷或鎳鏈作為電極并采用密度泛函理論和非平衡態(tài)格林函數(shù)相結(jié)合的計(jì)算方法,我們?cè)O(shè)計(jì)了幾種以1,6-亞甲基[10]輪烯分子為基礎(chǔ)的分子自旋電子器件并研究了其自旋相關(guān)的電輸運(yùn)性能和光電性能。在本文的第一章我們主要介紹了分子器件的研究現(xiàn)狀和背景,第二章介紹了論文計(jì)算中所用到的理論知識(shí),包括玻恩-奧本海默近似、哈特利-�？私坪兔芏确汉碚�,在使用密度泛函理論計(jì)算時(shí)會(huì)涉及基函數(shù)的選取問題,我們會(huì)在第三章詳細(xì)闡述。在第三章和第四章我們以過渡金屬鏈為電極構(gòu)建了兩種不同結(jié)構(gòu)的分子器件,并計(jì)算了其在電極磁性方向不同時(shí)的電流和光電流。我們的結(jié)果表明,這些器件具有非常突出的自旋過濾效應(yīng)和巨磁阻效應(yīng),其中用鎳金屬鏈作電極時(shí)具有最佳的電輸運(yùn)性能,所以器件結(jié)構(gòu)的不同對(duì)其輸運(yùn)性能的影響巨大。我們進(jìn)一步研究了用鎳金屬鏈作為電極時(shí)器件的自旋極化的光電流表現(xiàn),并且發(fā)現(xiàn)當(dāng)直接用紅外、可見或紫外線光照射器件時(shí),可以生成自旋極化的光電流,但相應(yīng)的微觀機(jī)制是不同的。更重要的是,如果兩個(gè)電極的磁化方向是反平行的,自旋方向不同的光電流會(huì)在空間上分開,從不同的電極流出,這個(gè)結(jié)論為同時(shí)生成兩種自旋光電流提供了一種新的思路。
[Abstract]:With the development of electronics and miniaturization of electronic devices, it has become a trend to construct electronic components with various functions by using single molecule or cluster, such as organic small molecule and biological molecule. At the same time, the study and measurement of the electrical or optical properties of these molecular devices has gradually developed into an independent subject, that is, molecular electronics. With the continuous development and improvement of measurement methods, molecular electronics has made substantial progress in both experiment and theory. It is precisely because the electrical transport property plays a vital role in the performance of molecular devices, so it is of great significance to study the electrical transport mechanism of molecular devices. Organic molecules are considered as one of the most popular materials for structuring molecular devices because of their weak spin orbital coupling effect and hyperfine interaction. One of the most promising organic molecules is 1,1-methylene [10] rotorene, which has a unique geometric structure and unique electronic properties. Due to its stable 蟺-conjugated electronic structure and remarkable aromatic properties, the molecule is also an ideal subject for experimental study. So far, however, little research has been done on the theory of electrical transport of the molecule. In this paper, iron, cobalt or nickel chains are used as electrodes, and the density functional theory is combined with the non-equilibrium Green's function. We have designed several molecular spin electronic devices based on the 1 '6-methylene-[ 10] rotorene molecule, and studied their spin dependent electrical transport and optoelectronic properties. In the first chapter of this paper, we mainly introduce the research status and background of molecular devices. In the second chapter, we introduce the theoretical knowledge used in the calculation, including Boon-Oppenheimer approximation, Hartley-Fogg approximation and density functional theory. The selection of basis functions is involved in the calculation of density functional theory, which is discussed in chapter 3. In the third and fourth chapters, we have constructed two kinds of molecular devices with different structures using transition metal chains as electrodes, and calculated the current and photocurrent in different magnetic directions of the electrodes. Our results show that these devices have very prominent spin filtering effect and giant magnetoresistive effect, among which nickel metal chains have the best electrical transport performance when used as electrode, so the structure of the devices has a great influence on their transport performance. We further study the photocurrent behavior of spin polarization when nickel metal chain is used as the electrode, and we find that when the device is irradiated directly with infrared, visible or ultraviolet light, the spin polarization photocurrent can be generated. But the corresponding micro-mechanism is different. More importantly, if the magnetization direction of the two electrodes is antiparallel, the photocurrent with different spin directions will be separated in space and outflow from different electrodes. This conclusion provides a new idea for the generation of two kinds of spin photocurrent simultaneously.
【學(xué)位授予單位】：太原理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：O469

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相關(guān)期刊論文 前2條

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本文編號(hào)：1901352