论文标题
相关带绝缘子中质量不平衡和挫败感的相互作用
Interplay of mass imbalance and frustration in correlated band insulators
论文作者
论文摘要
我们通过在Hubbard模型的一种变体中引入质量不平衡，在平方晶格上半填充时，通过引入质量不平衡（被称为离子Hubbard模型），在$ SU（2）$对称性上明显破坏了$ su（2）$对称性，从而报告了外来磁性金属相的出现或扩展。离子哈伯德模型还具有跳跃（$ \ sim t $）和现场库仑排斥（$ \ sim u $），这是一个交错的离子电位（$ \simΔ$），它破坏了基础lattice的转化对称性。在$ U $和$δ$的低至中间范围内，我们使用无限制的Hartree-fock理论来在$ U-u-δ$平面中构建相图，以固定质量不平衡（$ \simη$）。 Where as in the limit where both $U,Δ$ are comparable and much larger than the first $(\sim t_σ)$ and second $(\sim t_σ')$ neighbor hopping amplitudes , we employ the technique of generalized Gutzwiller approximation and subsequently use renormalized mean field theory to construct the phase diagram for varying values of hopping asymmetry.在这两种情况下，从具有弱抗磁性自旋密度波顺序的相关带绝缘子开始，如果我们调整$ u/δ$，我们会观察到开放新型的磁有序金属相，例如旋转失衡的铁磁金属，铁磁金属和抗毒素磁性半金属。我们还研究了在质量不平衡的情况下，在该模型的强耦合极限下，在D波和扩展的S波通道中研究单线超导性。
We report the emergence or broadening of exotic magnetic metallic phases upon explicit breaking of $SU(2)$ symmetry by introduction of mass imbalance in a variant of Hubbard model, known as the ionic Hubbard model in the presence of frustration at half-filling on a square lattice. The ionic Hubbard model has in addition to hopping($\sim t$) and onsite coulomb repulsion ($\sim U$), a staggered ionic potential ($\sim Δ$) which breaks translational symmetry of the underlying lattice. In the low to intermediate ranges of $U$ and $Δ$, we use unrestricted Hartree-Fock theory to construct the phase diagram in the $U-Δ$ plane for a fixed mass imbalance($\simη$). Where as in the limit where both $U,Δ$ are comparable and much larger than the first $(\sim t_σ)$ and second $(\sim t_σ')$ neighbor hopping amplitudes , we employ the technique of generalized Gutzwiller approximation and subsequently use renormalized mean field theory to construct the phase diagram for varying values of hopping asymmetry. In both cases, starting from a correlated band insulator with weak antiferromagnetic spin density wave order, if we tune $U/Δ$, we observe the opening of novel magnetically ordered metallic phases such as spin imbalanced ferromagnetic metal, ferrimagnetic metal and antiferromagnetic half metal. We also study singlet superconductivity in the d-wave and extended s-wave channels in the strong coupling limit of this model in the presence of mass imbalance.
