论文标题
在抗铁磁哈伯德模型中空间不均匀状态的竞争
Competition of spatially inhomogeneous states in antiferromagnetic Hubbard model
论文作者
论文摘要
在这项工作中，我们研究了弱耦合方案中三维立方晶格上各向异性哈驼模型的零温度阶段。众所周知，在半填充时，该模型的基态是抗磁磁性的（相称的旋转密度波）。对于非零掺杂，可以出现各种类型的空间不均匀相，例如相分离状态和具有域壁（“ Soliton lattice”）的状态。使用平均场理论，我们评估了这些阶段的自由能，以确定其中哪个可以成为小掺杂极限的真实基态。我们的研究表明，所有讨论的状态的自由能彼此非常接近。这些能量差异的较小性表明，对于真实材料而言，许多因素，该因素不受模型不明显，可以任意改变竞争阶段的相对稳定性。这进一步意味着，在特定的多个特定系统中，纯粹的理论预测是不可靠的。
In this work we study zero-temperature phases of the anisotropic Hubbard model on a three-dimensional cubic lattice in a weak coupling regime. It is known that, at half-filling, the ground state of this model is antiferromagnetic (commensurate spin-density wave). For non-zero doping, various types of spatially inhomogeneous phases, such as phase-separated states and the state with domain walls ("soliton lattice"), can emerge. Using the mean-field theory, we evaluate the free energies of these phases to determine which of them could become the true ground state in the limit of small doping. Our study demonstrates that the free energies of all discussed states are very close to each other. Smallness of these energy differences suggests that, for a real material, numerous factors, unaccounted by the model, may arbitrary shift the relative stability of the competing phases. This further implies that purely theoretical prediction of the true ground state in a particular many-fermion system is unreliable.
