First-principles study of the pentacene/Cu(111) interface: Adsorption states and vacuum level shifts
First-principles study of the pentacene/Cu(111) interface: Adsorption states and vacuum level shifts
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DOI：
10.1016/j.elspec.2009.04.005
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发表时间：
2009-08-01
影响因子：
1.9
通讯作者：
Morikawa, Yoshitada
中科院分区：
文献类型：
--
作者：
Toyoda, Kenji;Nakano, Yosuke;Morikawa, Yoshitada
我们采用密度泛函理论（DFT）和货车德瓦尔斯密度泛函[vdW-DF]方法研究了并五苯与Cu（111）表面的相互作用. M. Dion，H. Rydberg，E. Schroder，D.C. Langreth，B.I. Lundqvist，Phys. Rev. Lett. 92（2004）246401]。vdW-DF能准确地预测吸附能，而GGA和vdW-DF都高估了并五苯与金属基底之间的平衡距离（Z（C））。功函数的变化显著地依赖于Z（C）。实验功函数的变化可以成功地再现GGA，如果实验报告的吸附几何形状被使用，而功函数的变化的幅度被低估，如果计算的吸附几何形状被应用。我们研究了IDIS模型IH。巴斯克斯河Qszwaldowski，R Pou，J. Ortega，R.佩雷斯角，澳-地弗洛雷斯，A.卡恩，欧洲天体物理学。Lett. 65（2004）802]以将其与GGA结果进行比较。IDIS模型估算的界面偶极子与GGA结果相当一致，只要吸附距离较大。另一方面，当吸附距离变小时，它们倾向于偏离GGA结果，其中发生从金属表面到吸附物的反馈。我们的分析表明，在实验报告的金属有机距离，回捐赠是显着的，足以引起垂直于表面的并五苯分子的极化，这导致功函数的减少。因此，在实验报告的金属有机物的距离，由一个简单的IDIS模型估计的功函数的变化偏离计算的自洽GGA计算。我们还发现，在实验报道的金属-有机距离处，转移的电子在并五苯和Cu（111）表面之间产生弱化学键，说明并五苯的反应性性质。(C)2009 Elsevier B. V.保留所有权利。
We have studied the interaction of pentacene with a Cu(1 1 1) surface using density functional theory (DFT)within a generalized gradient approximation (GGA) and the van der Waals density functional [vdW-DF. M. Dion, H. Rydberg, E. Schroder, D.C. Langreth, B.I. Lundqvist, Phys. Rev. Lett. 92 (2004) 246401]. The adsorption energy is accurately predicted by vdW-DF, while the equilibrium distances between pentacene and the metal substrate (Z(C)) are overestimated by both GGA and vdW-DF. The work function changes depend significantly on Z(C). The experimental work function change can be Successfully reproduced by GGA if the experimentally reported adsorption geometry is used, whereas the magnitude of the work function change is underestimated if calculated adsorption geometries are applied. We examined the IDIS model I H. Vazquez, R. Qszwaldowski, R Pou, J. Ortega, R. Perez, F. Flores, A. Kahn, Europhys. Lett. 65 (2004) 802] to compare it with the GGA results. The interface dipoles estimated by the IDIS model fairly agree with the GGA results, provided that the adsorption distance is large. On the other hand, they tend to deviate from the GGA results as the adsorption distance becomes smaller, where back donation from the metal surface to the adsorbate occurs. Our analysis reveals that at experimentally reported metal-organic distance, back donation is significant enough to induce polarization of pentacene molecules perpendicular to the surface, which leads to a reduction of the work function. Thus, at the experimentally reported metal-organic distance, the work function change estimated by a simple IDIS model deviates from that calculated by self-consistent GGA calculations. We also found that at the experimentally reported metal-organic distance, the transferred electrons create weak chemical bonds between pentacene and the Cu(1 1 1) surface, illustrating the reactive nature of pentacene. (C) 2009 Elsevier B.V. All rights reserved.