Nematic Ferromagnetism on the Lieb Lattice

作     者：陈科技 张威 

作者机构：Department of Physics Renmin University of China Beijing 100872 Beijing Key Laboratory of Opto-electronic Functional Materials and Micro-nano Devices Renmin University of China Beijing 100872 

出 版 物：《Chinese Physics Letters》 (中国物理快报（英文版）)

年 卷 期：2014年第31卷第11期

页      面：14-17页

核心收录：

学科分类：07[理学] 08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 070201[理学-理论物理] 0702[理学-物理学] 

基　　金：Supported by the National Natural Science Foundation of China under Grant Nos 10904172 and 11274009  the Research Funds of Renmin University of China under Grant Nos 14XNH061 and 10XNL016  and the Program of State Key Laboratory of Quantum Optics and Quantum Optics Devices under Grant No KF201404 

主　　题：FERROMAGNETISM CONDENSED matter physics LATTICE theory ROTATIONAL symmetry NEMATOCIDES 

摘      要：We discuss the properties of ferromagnetic orders on the Lieb lattice and show that a symmetry protected quadratic-fiat band crossing point will dramatically affect the magnetic ordering. In the presence of a weak on-site repulsive interaction, the ground state is a nematic ferromagnetic order with simultaneously broken time-reversal and rotational symmetries. When the interaction strength increases, the rotational symmetry will restore at a critical value, and the system enters a conventional ferromagnetic regime. The mean-field transition temperatures for both the nematic and conventional ferromagnetic phases are in the order of interaction. This observation suggests that these magnetic orders have the potential to be realized and detected in cold atomic systems within realistic experimental conditions.