关联电子体系的软量子相

项目名称： 关联电子体系的软量子相

项目编号： No.11474287

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 邹良剑

作者单位： 中国科学院合肥物质科学研究院

项目金额： 90万元

中文摘要： 强关联电子材料中多个量子相接近简并并相互竞争和合作有可能导致向列相和相分离等各种新奇量子相；然而目前的唯象理论未能给出这些软量子相的微观起源及其实验结果的分散性，导致了对它们是否存在的极大争议。本项目提出研究几类典型关联电子体系铜氧和铁基等化合物中电子向列相和电子相分离的微观起源和表征；利用我们发展的多轨道隶玻色子和变分蒙特卡洛等多体方法，通过研究两带和三带有效微观模型中电子向列相和分离相等量子相对在位和长程库仑关联、洪特耦合、掺杂等各种物理参数下的稳定性和相图，及其导致的各种物理性质随温度的依赖行为，揭示长程库仑关联和熵对稳定软量子相的机制，阐述除自旋和轨道的量子涨落外短程电荷序和温度涨落对这些量子相的影响，建立起系统自洽的软量子相的物理图像。该项目有助于人们理解关联电子体系铜基和铁基等化合物中各种反常性质，将为实验工作者探索发现新规律和新现象以及新型功能的电子材料提供有益的参考。

中文关键词： 电子向列相；强关联电子体系；高温超导；赝能隙；量子相变

英文摘要： The nearly degeneracy, competition and cooperative behaviors of multiple quantum phases in strongly correlated materials may lead to marvelous electronic nematic and segregated phases; however, the present phenomenological theories do not disclose microscopic origin and explicit experimental characters based on solid analysis to realistic models, resulting great debates on the existence of these quantum phases. We propose in this project to theoretically study the stability and phase diagrams of electronic nematic, segregated and other soft quantum phases, and temperature dependences of various physical properties in two-band and three-band effective microscopic models for various on-site and long-range Coulomb correlation, Hund's rule coupling and doping by utilizing the multi-orbital slave boson approaches, variational Monte Carlo, and other self-consistent many-body methods, to elucidate the microscopic mechanism of the long-range Coulomb correlations and entropy in stabilizing these soft quantum phases, to address the influences of short-range charge order and thermal fluctuations, in addition to spin and orbital fluctuations, on these unusual phases, and to establish a self-consistent and complete novel scenarios of these soft quantum phases. This project will not only benefit our understanding to rich phase diagrams and anomalous properties in high-temperature superconducting cuprates and ironpnictides, but also provide useful clues for experimentists to discover novel phenomena and new electronic material with particular functions.

英文关键词： electronic nematic phase;strongly correlated systems;high temperature superconductors;Pseudogap;Quantum phase transition