论文标题
氧化物材料中的相分离和配对波动
Phase separation and pairing fluctuations in oxide materials
论文作者
论文摘要
我们研究了电荷不稳定性的微观机制和具有强电子相关性的系统中不均匀状态的形成。已经证明，在强耦合膨胀中，单频段哈伯德模型显示出朝着相位分离的不稳定，并扩展了用于分析Hubbard-Kanamori Hamiltonian中相位分离作为原型多型模型的方法。我们研究了不均匀条带状态的配对波动，在该条带状态下，在扩展的S波和D波通道中的超导相关性对应于两粒子光谱中的（抗）结合状态。尽管扩展的S波波动与局部相互作用参数U的规模相关，但我们发现D波波动在越过费米水平的活动子带的能量范围内发音。结果，低能自旋和电荷波动可以将D波相关性从结合状态传递到低能准粒子带。因此，我们的研究有助于了解丘比特中的条纹相关性和D波超导性的共存。
We investigate the microscopic mechanism of charge instabilities and the formation of inhomogeneous states in systems with strong electron correlations. It is demonstrated that within a strong coupling expansion the single-band Hubbard model shows an instability towards phase separation and extend the approach also for an analysis of phase separation in the Hubbard-Kanamori hamiltonian as a prototypical multiband model. We study the pairing fluctuations on top of an inhomogeneous stripe state where superconducting correlations in the extended s-wave and d-wave channels correspond to (anti)bound states in the two-particle spectra. Whereas extended s-wave fluctuations are relevant on the scale of the local interaction parameter U, we find that d-wave fluctuations are pronounced in the energy range of the active subband which crosses the Fermi level. As a result low energy spin and charge fluctuations can transfer the d-wave correlations from the bound states to the low energy quasiparticle bands. Our investigations therefore help to understand the coexistence of stripe correlations and d-wave superconductivity in cuprates.
