The semi-quantum two-orbital exchange model is used to investigate the effect of small rare-earth ion substitution on orthorhombic RMnO 3 with A-type antiferromagnetic order,using the Monte Carlo algorithm,exact diago...The semi-quantum two-orbital exchange model is used to investigate the effect of small rare-earth ion substitution on orthorhombic RMnO 3 with A-type antiferromagnetic order,using the Monte Carlo algorithm,exact diagonalization,and zero-temperature optimization approaches.It is revealed that the substitution results in a rich multiferroic phase diagram where the coexisting A-type antiferromagnetic phase and spiral spin phase,pure spiral spin phase,coexisting spiral spin phase,the E-type antiferromagnetic phase,and the pure E-type antiferromagnetic phase emerge in sequence.The multiferroic phase transitions modulate substantially the electric polarization,which is consistent qualitatively with recent experiments.展开更多
The generalized quantum Monte Carlo algorithm is developed and used to calculate the energy,occupation numbers,and correlations functions of finite FeAs clusters in the two-orbital model at finite temperatures.The cod...The generalized quantum Monte Carlo algorithm is developed and used to calculate the energy,occupation numbers,and correlations functions of finite FeAs clusters in the two-orbital model at finite temperatures.The coding of quantum states made it possible to take into account complex exchange terms between the orbitals.The results for the calculation of the thermodynamic characteristics of finite two-dimensional FeAs clusters simulating iron-based superconductors have been obtained.The calculated correlation functions indicate the possibility of the effective attraction of charge carriers.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 51031004,11004027,and 11074113)the National Basic Research Program of China (Grant Nos. 2011CB922101 and 2009CB929501)the Priority Academic Program Development of Jiangsu Provincial Higher Education Institutions,China
文摘The semi-quantum two-orbital exchange model is used to investigate the effect of small rare-earth ion substitution on orthorhombic RMnO 3 with A-type antiferromagnetic order,using the Monte Carlo algorithm,exact diagonalization,and zero-temperature optimization approaches.It is revealed that the substitution results in a rich multiferroic phase diagram where the coexisting A-type antiferromagnetic phase and spiral spin phase,pure spiral spin phase,coexisting spiral spin phase,the E-type antiferromagnetic phase,and the pure E-type antiferromagnetic phase emerge in sequence.The multiferroic phase transitions modulate substantially the electric polarization,which is consistent qualitatively with recent experiments.
基金supported by the Russian Foundation for Basic Research(Project Nos.14-08-00509 and 12-02-00261).
文摘The generalized quantum Monte Carlo algorithm is developed and used to calculate the energy,occupation numbers,and correlations functions of finite FeAs clusters in the two-orbital model at finite temperatures.The coding of quantum states made it possible to take into account complex exchange terms between the orbitals.The results for the calculation of the thermodynamic characteristics of finite two-dimensional FeAs clusters simulating iron-based superconductors have been obtained.The calculated correlation functions indicate the possibility of the effective attraction of charge carriers.
