Beijing Computational Science Research Center , Beijing 100084, China.
Sci Rep. 2012;2:922. doi: 10.1038/srep00922. Epub 2012 Dec 4.
Understanding magnetism and electron correlation in many unconventional superconductors is essential to explore mechanism of superconductivity. In this work, we perform a systematic numerical study of the magnetic and pair binding properties in recently discovered polycyclic aromatic hydrocarbon (PAH) superconductors including alkali-metal-doped picene, coronene, phenanthrene, and dibenzopentacene. The π-electrons on the carbon atoms of a single molecule are modelled by the one-orbital Hubbard model, and the energy difference [Formula: see text] between carbon atoms with and without hydrogen bonds is taking into account. We demonstrate that the spin polarized ground state is realized for charged molecules in the physical parameter regions, which provides a reasonable explanation of local spins observed in PAHs. In alkali-metal-doped dibenzopentacene, our results show that electron correlation may produce an effective attraction between electrons for the charged molecule with one or three added electrons.
理解许多非常规超导体中的磁性和电子关联对于探索超导机制至关重要。在这项工作中，我们对最近发现的多环芳烃（PAH）超导体中的磁和对键合性质进行了系统的数值研究，包括碱金属掺杂的并五苯、苉、菲和二并五苯。单个分子中碳原子上的π电子由单轨道 Hubbard 模型建模，并且考虑了具有和不具有氢键的碳原子之间的能量差 [Formula: see text]。我们证明，在物理参数区域内，带电分子实现了自旋极化的基态，这为在 PAH 中观察到的局部自旋提供了合理的解释。在碱金属掺杂的二并五苯中，我们的结果表明，电子关联可能会在带有一个或三个附加电子的带电分子之间产生电子之间的有效吸引力。
