论文标题
半填充的扩展哈伯德模型的旋转和电荷调制
Spin and charge modulations of a half-filled extended Hubbard model
论文作者
论文摘要
我们介绍和分析了一个扩展的哈伯德模型，其中，在该模型中，库仑相互作用以及交错的局部电势（SLP）在半个频带填充的方形晶格上，在热力学极限下。使用Hartree-Fock近似以及Kotliar和Ruckenstein Slave Boson形式主义，我们表明该模型在有限的SLP值下具有电荷订单（CO）以及联合自旋和电荷调制（SCO），而自旋密度波（SDW）仅稳定下来，以使SLP稳定下来。我们确定其相位边界以及依赖SLP的顺序参数的变化，以及现场和最近的邻居相互作用。 CO和SCO相共存的结构域，适用于电阻开关实验。我们表明，当采取零-SLP限制时，新型的SCO系统地变成了更常规的SDW相。我们还讨论了在零和有限温度下不同相变的性质。在前一种情况下，没有连续CO到SDW（或SCO）相变。相比之下，伴随有限温度下的顺磁相（PM），该相（PM）伴随着连续的相变向自旋或电荷有序相。证明了与数值模拟的良好定量一致性，并进行了两种使用方法之间的比较。
We introduce and analyze an extended Hubbard model, in which intersite Coulomb interaction as well as a staggered local potential (SLP) are considered, on the square lattice at half band filling, in the thermodynamic limit. Using both Hartree-Fock approximation and Kotliar and Ruckenstein slave boson formalism, we show that the model harbors charge order (CO) as well as joint spin and charge modulations (SCO) at finite values of the SLP, while the spin density wave (SDW) is stabilized for vanishing SLP, only. We determine their phase boundaries and the variations of the order parameters in dependence on the SLP, as well as on the on-site and nearest-neighbor interactions. Domains of coexistence of CO and SCO phases, suitable for resistive switching experiments, are unraveled. We show that the novel SCO systematically turns into the more conventional SDW phase when the zero-SLP limit is taken. We also discuss the nature of the different phase transitions, both at zero and finite temperature. In the former case, no continuous CO to SDW (or SCO) phase transition occurs. In contrast, a paramagnetic phase (PM), which is accompanied with continuous phase transitions towards both spin or charge ordered phases, sets in at finite temperature. A good quantitative agreement with numerical simulations is demonstrated, and a comparison between the two used approaches is performed.
