新型巡游电子系统中的关联效应和量子相变

项目名称： 新型巡游电子系统中的关联效应和量子相变

项目编号： No.11274084

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 数理科学和化学

项目作者： 戴建辉

作者单位： 杭州师范大学

项目金额： 78万元

中文摘要： 电子关联与量子涨落及由此所致量子态之竞争、共存是凝聚态物理的重要课题。铁基超导化合物作为新型多轨道磁性金属体系，不仅可呈超导电性，还呈超导与磁性共存、超导向重费米子过渡、空位有序等独特而重要的新现象，从而产生诸多新问题与新挑战。本项目拟以稀土铁砷材料和含铁空位铁硒材料为例，从相互作用多电子模型出发，发展运用平均场和有效场论等分析方法，结合数值重整化群、第一性原理计算等数值方法，系统性地研究这类新型巡游电子系统两个方面的电子关联效应。主要内容包括：（1）由3d电子和4f电子的相互作用导致的超导或反铁磁坏金属到重费米子的过渡及伴随的费米面拓扑结构变化、量子相变；（2）由空位有序和相互作用联合驱动的金属绝缘体相变、轨道有序、及超导与磁性的共存或近邻效应等。这些研究旨在认识复杂磁性金属材料中各种关联作用随掺杂压力等参数调控的规律以及它们对超导电性、低温运输与磁性的影响，解释或预言新的物理现象。

中文关键词： 电子结构；电子关联；铁基材料；量子相变；量子磁性

英文摘要： The interplay between electron correlations and quantum fluctuations, which may result in various competing or co-existing quantum states, has been an important theme in modern condensed matter physics. A new challenge to this theme comes from the recently discovered iron-based superconductors, where several new phenomena, including the co-existence of superconductivity and magnetic order, the crossover from antiferromagnetism or superconductivity to heavy fermions, as well as various new properties associated with the Fe-vacancy ordering, has been emerged in addition to the unconventional superconductivity. In this Project, we will systematically investigate the roles the electron correlations play on the aforementioned novel phenemena in two prototypes of multi-orbital magnetic metals as exemplified by the rare earth iron pnictides and the Fe-vacancy ordered iron chalcogenides. For this purpose, a combinational approach to the microscopic many-body models describing the interacting electrons will be adopted, mainly based on the mean field and effective quantum field theories, assisted by the efficient numerical renormalization group, the first principle simulations and some other numerical methods. The main topics will be focused on but not limited to : (1) the interplay of the 3d-electrons and 4f-electro

英文关键词： electronic structure；electron correlation；iron pnictides；quantum phase transitions；quantum magnetism