外加电场对自旋霍尔效应的影响

影响自旋霍尔效应的因素有很多,通过对由平面电场诱导的自旋-轨道耦合对Rashba二维电子气中的本征自旋霍尔效应的影响的研究,表明:当这个由平面电场诱导的自旋-轨道耦合考虑进去之后,在无序的Rash-ba二维电子气中会存在稳定的静态本征自旋霍尔效应.所得到的静态本征自旋霍尔电导呈现出与原先理论设想相符的一些有趣的特征.     

Rashba自旋轨道耦合下宽量子线中的自旋流

利用硬壁限制势下Rashba自旋轨道耦合量子线波函数以及一个自旋流定义来计算宽量子线中的自旋流密度,得到了两个非零线自旋流密度分量及一个净自旋流密度,发现随着量子线通道数及Rashba自旋轨道耦合作用的增加以上三个自旋流密度会随之增强,此外利用自旋流产生的可被检测电场可提供一个对自旋流进行检测和调控的方法.     

Rashba多量子阱异质结中自旋轨道耦合效应对电子输运的影响

根据量子相干输运理论,利用传递矩阵的方法,研究自旋电子在铁磁体（F）／半导体多量子阱（SWM）／铁磁体的一维结构中,考虑自旋轨道耦合效应时的量子相干输运的特性．通过计算发现在这种一维多量子阱结构中的自旋电子的输运特性发生了一定的变化．这有利于进一步提高自旋电子的隧穿系数和自旋极化率．     

自旋三极管中电子隧穿系数的数学推导

利用传递矩阵方法，在同时考虑自旋轨道耦合效应和量子尺寸效应情况下，分别计算了没有外场、外加磁场、电场时，透射概率的变化关系。     

基于自旋轨道耦合效应的能带分裂机理

从理论上导出了自旋与p轨道耦合效应使能带分裂的具体表达式,阐明了能带分裂的物理机理,讨论了自旋轨道耦合效应使价带顶分裂后能带结构的特征。其结果有助于更深刻的理解自旋轨道耦合引起能带分裂的机理,对研究半导体光学选择定择、输运性质及应变量子阱中能带的分裂也提供了重要的理论基础。     

固体磁性的量子调控

本文介绍自旋电子学研究领域中近期十分活跃的方向之一:固体磁性的量子调控。重点介绍包括利用自旋极化电流来调控磁矩的自旋转移矩效应、利用电场来调控体系磁性及磁电耦合效应、利用光场来调控磁性的飞秒磁学以及利用温度梯度来产生电动势的自旋塞贝克效应等的最新研究进展。     

自旋场效应晶体管中极化输运特性研究

自旋极化电流从铁磁金属注入到半导体的主要障碍是铁磁体和半导体电导率的不匹配。但最近研究结果表明可以通过运用适当的方法来克服这个困难。我们基于自旋场效应晶体管的模型及Landauer-Buttiker公式,求得电子通过半导体异质结的电导,得出了自旋电子器件中极化电荷的输运特性。     

基于InAs/GaAs异质结的δ掺杂磁半导体纳米结构的电子自旋输运

本文研究了基于InAs/GaAs异质结的δ掺杂磁纳米结构的电子自旋输运性质。计算了透射系数、电导和自旋极化。主要分析和讨论了δ掺杂的权重和位置对电子自旋极化输运的影响。结果表明,δ掺杂权重的增加可以显著抑制电子的透射系数和电导。通过改变δ掺杂的权重和位置可以实现较大程度的自旋极化。研究结果将有助于理解δ掺杂磁纳米结构中的实验现象和设计δ掺杂可调制自旋电子器件。     

非磁性掺杂下石墨烯纳米带的自旋输运

基于第一性原理的密度泛函理论和非平衡格林函数方法,研究了边界掺杂下锯齿型石墨烯纳米带(ZGNRs)中的自旋输运性质,结果显示:在ZGNRs边缘,利用单个铝(Al)或磷(P)原子替换碳原子后,ZGNRs中的电子输运呈现强烈的自旋效应.特别地,在Al掺杂的偶数个原子宽度的ZGNRs中,上自旋电流随着电压单调增长,而下自旋电流在1伏偏压左右出现明显的负微分电阻效应(NDR).其主要原因是替换边缘C原子的Al(P)原子为施主(受主)杂质,一方面使透射谱或电导发生自旋极化,另一方面在透射谱上杂质态在费米能之上(下)引入了一个透射谷.     

磁调制量子结构的自旋过滤特性

基于杂化磁调制量子结构,我们从理论上提出了一电子自旋过滤器,并研究了其自旋输运性质.实验上,其可以通过在半导体异质结表面沉积磁化方向不同的铁磁条带形成.通过对真实InAs 材料系统的计算,发现这种系统具有很强的电子自旋极化效应,其自旋极化度在共振时几乎达到100%.因此,该结构可以用于电子自旋过滤器.     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

Western and Eastern culture differences in commercial field

The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity.     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

风的曲线

Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.     

团图为数的图中的闭团贯数

Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.