首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  免费   3篇
  国内免费   1篇
物理学   4篇
  2013年   1篇
  2012年   1篇
  2006年   1篇
  2003年   1篇
排序方式: 共有4条查询结果,搜索用时 31 毫秒
1
1.
We study theoretically the essential properties of an exciton in vertically coupled Gaussian quantum dots in the presence of an external magnetic field. The ground state energy of a heavy-hole exciton is split into four energy levels due to the Zeeman effect. For the symmetrical system, the entanglement entropy of the exciton state can reach a value of 1. However, for a system with broken symmetry, it is close to zero. Our results are in good agreement with previous studies.  相似文献   
2.
沈曼  张亮  刘建军 《物理学报》2012,61(21):388-393
在In0.6Ga0.4As/GaAs量子点中,采用一维等效势模型和有限差分法理论计算了激子态的性质,得到了激子跃迁能和束缚能随磁场、横向束缚强度以及量子点尺寸的变化关系.结果表明:加入磁场后,Zeeman效应使得激子的能级简并度解除,激子的基态跃迁能与实验符合得很好;横向束缚强度或磁场强度的增加使得激子的束缚增强;量子点的尺寸对激子的束缚产生重要的影响;通过电子-空穴间平均距离以及激子体系波函数分布图像分析了其产生的物理机制.  相似文献   
3.
We develop a microscopic theory of the nematic phase with consideration of the effect of the collective excitation on properties of nematic liquid crystals. The model is based on the Heisenberg's exchange model of the ferromagnetic materials. Since the orientation of the molecular long axis and the angular momentum of the molecule rotating around its long axis have the same direction, operators can be introduced to research the nematic liquid crystals. Using the lattice model and the Holstein-Primakoff transformation, the Hamiltonian of the system can be obtained, which has the same form as that of the ferromagnetic substance. The relation between the order parameter and reduced temperature can be gotten. It is in good agreement with the experimental results in the low temperature region, the accordance is better than that of the molecular field theory and the computer simulation. In high temperature region close to the transition point, by considering the effect of the higher-order terms in the Hamiltonian, theoretical prediction is in better agreement with the experiment. That indicates the many-body effect is important to nematic liquid crystals.  相似文献   
4.
液晶中一种稳定的相态:蓝相   总被引:2,自引:0,他引:2  
刘建军  沈曼  杨国琛 《物理》2003,32(5):327-331
文章描述了胆甾相液晶中蓝相的研究现况.蓝相(BP)是液晶中具有特殊性质的一个相态,它的序参量表现出三维空间周期性.蓝相是出现在一个狭小的温度间隔里(量级为0.1—1K)的稳定相态.文章对已观察到的BPⅠ,BPⅡ,BPⅢ(“雾”相)的性质做了简要的叙述.对研究液晶蓝相的主要理论——Ginzburg-Landau理论(唯象理论)作了介绍,并指出了蓝相研究的实际物理意义。  相似文献   
1
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号