Department of Chemistry, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea.
Phys Rev Lett. 2012 Oct 26;109(17):177001. doi: 10.1103/PhysRevLett.109.177001. Epub 2012 Oct 23.
Based on the dynamical mean field theory and angle resolved photoemission spectroscopy, we have investigated the mechanism of high T(c) superconductivity in stoichiometric LiFeAs. The calculated spectrum is in excellent agreement with the measured angle resolved photoemission spectroscopy. The Fermi surface (FS) nesting, which is predicted in the conventional density functional theory method, is suppressed due to the orbital-dependent correlation effect within the dynamical mean field theory method. We have shown that such marginal breakdown of the FS nesting is an essential condition to the spin-fluctuation mediated superconductivity, while the good FS nesting in NaFeAs induces a spin density wave ground state. Our results indicate that a fully charge self-consistent description of the correlation effect is crucial in the description of the FS nesting-driven instabilities.
基于动力学平均场理论和角分辨光电子能谱，我们研究了化学计量比 LiFeAs 中超导高温的机制。计算得到的谱与实验测量的角分辨光电子能谱非常吻合。在传统的密度泛函理论方法中预测的费米面（FS）嵌套，由于动力学平均场理论方法中的轨道相关关联效应而被抑制。我们已经表明，FS 嵌套的这种边缘破坏是自旋涨落介导超导的必要条件，而 NaFeAs 中的良好 FS 嵌套则导致自旋密度波基态。我们的结果表明，在描述 FS 嵌套驱动的不稳定性时，对关联效应的完全电荷自洽描述是至关重要的。
