Interaction and spin–orbit effects on a kagome lattice at 1/3 filling

We investigate the competing effects of spin-orbit coupling and electron--electron interaction on a kagome lattice at 1/3 filling. We apply the cellular dynamical mean-field theory and its real-space extension combined with the continuous time quantum Monte Carlo method, and obtain a phase diagram including the effects of the interaction and the spin-orbit coupling at T = 0. 1t, where T is the temperature and t is the hopping energy. We find that without the spin-orbit coupling, the system is in a semi-metal phase stable against the electron--electron interaction. The presence of the spin-orbit coupling can induce a topological non-trivial gap and drive the system to a topological insulator, and as the interaction increases, a larger spin--orbit coupling is required to reach the topological insulating phase.     

LiBH4-xFx储氢材料的制备与性能研究

采用机械球磨方法制备不同球磨时间的LiBH4-xFx储氢材料。通过X射线衍射仪和DSC-TG同步热分析仪测试手段,研究LiBH4-xFx储氢材料的放氢温度以及其晶格特征形貌。结合DSC与XRD的测试结果,对于不同球磨时间所制的LiBH4-xFx样品,球磨24h制得的LiBH4-xFx样品放氢温度最低,即放氢主峰温度478℃。并且对于纯LiBH4熔融过程的热分解温度也降低了17℃。这是由于F部分取代LiBH4中H,LiBH4-xFx晶格形成的。     

浅析贬谪诗中的词汇衔接功能

词汇衔接是语篇衔接中的一个重要衔接手段,为篇章的连贯提供了基础。词汇在语篇中行式上的衔接体现了作者的交际意图,具有丰富的表达功能。在综合各种词汇衔接分类的基础上,深入探讨重复、同义、反义、上下义、搭配等词汇衔接方式,主要分析他们在贬谪诗这种特殊文体中的衔接功能。旨在进一步理解贬谪诗语篇的文体风格,从而更好地把语篇语言学的理论语用到实践中去。     

浅析概念整合理论对中国古典诗词的阐释

结合Fauconnier等人提出的概念整合理论的主要观点,从认知层面对中国古典诗词进行分析,通过构建整合与之相关的心理空间,结合相关背景知识,让读者领悟到作者的目的;结合案例分析可发现,一方面概念整合理论有助于人们理解中国诗词,另一方面该理论为人们研究诗人赋诗作词过程中的认知活动提供了一种有效的工具。     

Quantum phase transitions in two-dimensional strongly correlated fermion systems

In this article, we review our recent work on quantum phase transition in two-dimensional strongly correlated fermion systems. We discuss the metal−insulator transition properties of these systems by calculating the density of states, double occupancy, and Fermi surface evolution using a combination of the cellular dynamical mean-field theory (CDMFT) and the continuous-time quantum Monte Carlo algorithm. Furthermore, we explore the magnetic properties of each state by defining magnetic order parameters. Rich phase diagrams with many intriguing quantum states, including antiferromagnetic metal, paramagnetic metal, Kondo metal, and ferromagnetic insulator, were found for the two-dimensional lattices with strongly correlated fermions. We believe that our results would lead to a better understanding of the properties of real materials.     

Mn 位 Al 掺杂的六角结构 YMn1-xAlxO3(0≤x ≤0.1)单晶的磁性及受挫调制

用光学浮区法生长了 Mn 位 Al 掺杂的六角结构 YMn1 -x Alx O3 系列单晶样品, 对该样品的掺杂效应及磁受挫性质进行了研究. 结果发现, 在 YMnO3 的 Mn3 + 位掺入不同浓度的非磁性 Al3 + 离子对样品的磁化特性有很大的影响. 随着掺杂浓度的增加, 居里-外斯温度明显降低, 磁性受挫因子f 减小, 反铁磁转变温度向低温方向移动.由于 Al3 + 离子半径比 Mn3 + 小, 掺杂使得系统的晶格常数变小, Mn-Mn 键长变短, 最终导致交换积分减小. 另外, 由于非磁性的 Al3 + 离子部分替代 Mn3 + 离子直接破坏了 Mn3 + 离子间的交换路径, 结果使得体系的几何受挫被抑制,反铁磁转变温度降低, Mn3 + - Mn3 + 之间的 AFM 相互作用被大大削弱.