本文選題：狄拉克半金屬 + 量子反�；魻栃�(yīng)��； 參考：《清華大學(xué)》2016年博士論文

【摘要】：最近幾年,拓?fù)鋺B(tài)及對(duì)稱性保護(hù)的拓?fù)鋺B(tài)成為凝聚態(tài)物理研究的一個(gè)前沿和熱點(diǎn)。在本論文中我們主要討論了一些典型的拓?fù)鋺B(tài),結(jié)合理論模型和實(shí)際材料,我們預(yù)言了若干新的拓?fù)鋺B(tài)存在。我們主要在論文中討論以下三個(gè)方面的問題:二維狄拉克材料及量子反常霍爾效應(yīng),二維反鐵磁材料中的量子反�；魻栃�(yīng)及手征拓?fù)涑瑢?dǎo)相,和三維拓?fù)渚w絕緣體。首先,我們根據(jù)第一原理計(jì)算和解析有效模型提出了一類二維的狄拉克半金屬材料,其中一個(gè)典型的例子為(LaO)2(SbSe2)2。這類材料具有八個(gè)狄拉克錐,并且其特點(diǎn)在于狄拉克錐的性質(zhì)可以通過外加門電壓進(jìn)行調(diào)控,包括狄拉克錐存在與否,位置,費(fèi)米速度和各向異性。我們發(fā)現(xiàn)了這種可調(diào)控性的物理原因是體系中存在和原子層依賴的由自旋軌道耦合引起的自旋結(jié)構(gòu),并且狄拉克錐是被鏡面反射對(duì)稱性所保護(hù)的。更進(jìn)一步,如果我們?cè)隗w系中引入磁性,則可以實(shí)現(xiàn)高陳數(shù)的量子反�；魻栃�(yīng),并且體系的陳數(shù)也可以通過調(diào)節(jié)電場實(shí)現(xiàn)從4到0到-4的變化。其次,我們探究了另一種實(shí)現(xiàn)量子反�；魻栃�(yīng)的方法,發(fā)現(xiàn)在具有雙鈣鈦礦結(jié)構(gòu)的反鐵磁材料Sr2FeOsO6薄膜中,也可以通過外加電場產(chǎn)生能帶翻轉(zhuǎn)而實(shí)現(xiàn)量子反常霍爾效應(yīng)。更有趣的是,在這個(gè)體系中通過近鄰效應(yīng)引入超導(dǎo)配對(duì)項(xiàng)之后,可能實(shí)現(xiàn)二維的手征拓?fù)涑瑢?dǎo)態(tài)。最后,我們研究了三維拓?fù)渚w絕緣體,并進(jìn)行了分類。具有一個(gè)表面的三維拓?fù)渚w絕緣體的對(duì)稱性是由二維空間群來描述的。根據(jù)對(duì)稱性和能帶簡并的關(guān)系,我們找到了所有二維空間群可能對(duì)應(yīng)的非平庸的拓?fù)浔砻鎽B(tài),并給出了相應(yīng)體材料的拓?fù)洳蛔兞亢鸵恍┚唧w的模型來實(shí)現(xiàn)這樣的表面態(tài)。
[Abstract]:In recent years, topological states and symmetrically protected topological states have become a frontier and hotspot in condensed matter physics. In this paper, we mainly discuss some typical topological states. Combining with theoretical model and practical materials, we predict the existence of some new topological states. In this paper, we mainly discuss the following three aspects: two-dimensional Dirac material and quantum anomalous Hall effect, quantum anomalous Hall effect and chiral topological superconducting phase in two-dimensional antiferromagnetic material, and three-dimensional topological crystal insulator. Firstly, we propose a class of two-dimensional Dirac semi-metallic materials based on the first principle calculation and analytical efficient model. This kind of material has eight Dirac cones, and its characteristic is that the properties of Dirac cones can be controlled by external gate voltage, including the existence of Dirac cones, position, Fermi velocity and anisotropy. We find that the physical reason for this controllability is the spin structure of the system which is dependent on the atomic layer by the spin-orbit coupling, and the Dirac cone is protected by the mirror reflection symmetry. Furthermore, if we introduce magnetism into the system, we can realize the quantum anomalous Hall effect with high aging number, and the aging number of the system can change from 4 to 0 to -4 by adjusting the electric field. Secondly, we explore another method to realize the quantum anomalous Hall effect. It is found that the quantum anomalous Hall effect can also be realized in the antiferromagnetic Sr2FeOsO6 thin films with double perovskite structure by the energy band inversion produced by the applied electric field. More interestingly, it is possible to realize two-dimensional chiral topological superconducting states by introducing superconducting pairing terms through the nearest neighbor effect in this system. Finally, we study and classify the three-dimensional topological crystal insulators. The symmetry of three-dimensional topological crystal insulators with a surface is described by two-dimensional space groups. According to the relation between symmetry and energy band degeneracy, we find the non-mediocre topological surface states corresponding to all two-dimensional space groups, and give the topological invariants of the corresponding bulk materials and some concrete models to realize such surface states.
【學(xué)位授予單位】：清華大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：O469

【相似文獻(xiàn)】

相關(guān)期刊論文 前10條

1 ;中國科學(xué)家薛其坤首次在實(shí)驗(yàn)上發(fā)現(xiàn)量子反�；魻栃�(yīng)[J];發(fā)光學(xué)報(bào);2013年04期

2 ;我國科學(xué)家首次在實(shí)驗(yàn)中發(fā)現(xiàn)量子反�；魻栃�(yīng)[J];中國科技信息;2013年08期

3 李江濤;;我科學(xué)家首次在實(shí)驗(yàn)中發(fā)現(xiàn)量子反常霍爾效應(yīng)[J];前沿科學(xué);2013年01期

4 雷嘉;馬之恒;;我科學(xué)家觀測(cè)到量子反�；魻栃�(yīng)[J];世紀(jì)行;2013年04期

5 ;我國科學(xué)家率先觀測(cè)到量子反�；魻栃�(yīng)[J];中國計(jì)量;2013年05期

6 趙敬之;;中國科學(xué)家發(fā)現(xiàn)量子反�；魻栃�(yīng)[J];科學(xué);2013年03期

7 林莉君;李大慶;;我國科學(xué)家首次發(fā)現(xiàn)“量子反常霍爾效應(yīng)”[J];前沿科學(xué);2013年02期

8 ;中國科學(xué)家首次發(fā)現(xiàn)量子反�；魻栃�(yīng)[J];材料導(dǎo)報(bào);2013年07期

9 ;中國科學(xué)家首次發(fā)現(xiàn)量子反�；魻栃�(yīng)[J];功能材料信息;2013年02期

10 吳月輝;;我科學(xué)家首次成功實(shí)現(xiàn)“量子反�；魻栃�(yīng)”[J];共產(chǎn)黨員;2013年08期

相關(guān)會(huì)議論文 前1條

1 常翠祖;劉e，

本文編號(hào)：1858050