Department of Physics and Quantum Theory Project, University of Florida, Gainesville, Florida 32611, USA.
J Chem Phys. 2010 Feb 21;132(7):074702. doi: 10.1063/1.3291080.
We have used large-scale first-principles calculations based on density functional theory to investigate the structure, energetics, electronic, and magnetic structures of Fe(n)-doped C(60) monolayers supported by h-BN monolayer-covered Ni(111) surfaces. A systematic study of n-dependent physical properties has been performed (n=1-4,15). Binding energies on Fe atoms to the Fe(n-1)-C(60) complex have been calculated for n=1-4 after a thorough configuration search and structural optimization. The binding energy, electron charge transfer (from Fe(n) to C(60)), and magnetic moment all increase monotonically as functions of n. The electron charge transfer, ranging from approximately 1e(-) to 5e(-), is from the spin minority population. This leads to a situation in which the net spin of the C(60) molecule aligns with the spin minority and the magnetic moment in C(60) is opposite to the total magnetic moment of the system. For n=2, a competing antiferromagnetic state has been found. In this state, the net spin of the system as well as the C(60) is zero. Density of states and projected density of states analysis indicate that the system becomes metallic upon metal doping regardless its magnetic state. In addition, we have also performed calculations with the Hubbard U term (DFT+U) for two systems, n=4 and 15, to investigate possible gap opening near the Fermi surface.
我们使用基于密度泛函理论的大规模第一性原理计算，研究了在 h-BN 单层覆盖的 Ni(111)表面上支撑的 Fe(n)-掺杂 C(60)单层的结构、能量、电子和磁结构。我们对 n 依赖性物理性质进行了系统的研究(n=1-4,15)。在进行了彻底的构型搜索和结构优化后，我们计算了 n=1-4 时 Fe 原子与 Fe(n-1)-C(60)复合物的结合能。结合能、电子电荷转移(从 Fe(n)到 C(60))和磁矩都随着 n 的增加而单调增加。电子电荷转移范围约为 1e(-)至 5e(-)，来自自旋少数群体。这导致 C(60)分子的净自旋与自旋少数群体对齐，C(60)中的磁矩与系统的总磁矩相反。对于 n=2，我们发现了一个竞争的反铁磁状态。在这种状态下，系统以及 C(60)的净自旋为零。态密度和投影态密度分析表明，无论其磁状态如何，金属掺杂都会使系统变成金属。此外，我们还对两个系统(n=4 和 15)进行了带有 Hubbard U 项(DFT+U)的计算，以研究费米面附近可能的带隙打开。
