Variational Monte Carlo study of the nematic state in iron-pnictide superconductors with a five-orbital model  

作　　者：郑晓军 黄忠兵 邹良剑 

机构地区：[1]Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences [2]Faculty of Physics and Electronic Technology, Hubei University [3]Beijing Computational Science Research Center [4]Department of Physics, University of Science and Technology of China

出　　处：《Chinese Physics B》2015年第1期109-113,共5页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Grant Nos.11274310,11474287,11174072,and 91221103);the Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20104208110001)

摘　　要：We perform a variational Monte Carlo study of the nematic state in iron-pnictide superconductors within a realistic five-orbital model. Our numerical results show that the nematic state, formed by introducing an anisotropic hopping order into the projected wave function, is not stable unless the off-site Coulomb interaction V exceeds a critical value. This demonstrates that V plays a key role in forming the nematic state in iron-pnictide superconductors. In the nematic state,the orbital order and the anisotropic spin correlations are consistent with the experimental observations. We argue that the experimentally observed anisotropic magnetic couplings and structural transition are associated with the nematic state and can be understood in a unified framework.We perform a variational Monte Carlo study of the nematic state in iron-pnictide superconductors within a realistic five-orbital model. Our numerical results show that the nematic state, formed by introducing an anisotropic hopping order into the projected wave function, is not stable unless the off-site Coulomb interaction V exceeds a critical value. This demonstrates that V plays a key role in forming the nematic state in iron-pnictide superconductors. In the nematic state,the orbital order and the anisotropic spin correlations are consistent with the experimental observations. We argue that the experimentally observed anisotropic magnetic couplings and structural transition are associated with the nematic state and can be understood in a unified framework.

关 键 词：iron-pnictide superconductors nematic state off-site Coulomb interaction variational Monte Carlo simulation 

分 类 号：O511.3[一般工业技术—材料科学与工程]