Polarization-induced renormalization of molecular levels at metallic and semiconducting surfaces
Polarization-induced renormalization of molecular levels at metallic and semiconducting surfaces
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DOI：
10.1103/physrevb.80.245427
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发表时间：
2009-12-01
影响因子：
3.7
通讯作者：
Thygesen, K. S.
中科院分区：
文献类型：
--
作者：
Garcia-Lastra, J. M.;Rostgaard, C.;Thygesen, K. S.
基于第一性原理的G(0)W(0)计算，我们系统地研究了苯分子物理吸附在不同金属和半导体表面时，其电子能级如何因衬底极化而重整化。发现占据分子能级和未占据分子能级之间的能隙因极化而减小的程度与费米能级处衬底的态密度（对于金属）以及衬底带隙（对于半导体）成比例。这些结论通过对简单晶格模型的计算得到了进一步支持。通过用衬底的联合态密度来表示电子自能，我们将能级移动与表面电子结构联系起来，从而为GW和G(0)W(0)计算中的趋势提供了微观解释。虽然半局域和杂化交换 - 相关泛函无法捕捉镜像电荷效应，但我们发现误差抵消使得吸附分子的占据轨道的G(0)W(0)能和科恩 - 沈（Kohn - Sham）能之间具有非常好的一致性。
On the basis of first-principles G(0)W(0) calculations we systematically study how the electronic levels of a benzene molecule are renormalized by substrate polarization when physisorbed on different metallic and semiconducting surfaces. The polarization-induced reduction in the energy gap between occupied and unoccupied molecular levels is found to scale with the substrate density of states at the Fermi level (for metals) and substrate band gap (for semiconductors). These conclusions are further supported by calculations on simple lattice models. By expressing the electron self-energy in terms of the substrate's joint density of states we relate the level shift to the surface electronic structure, thus providing a microscopic explanation of the trends in the GW and G(0)W(0) calculations. While image charge effects are not captured by semilocal and hybrid exchange-correlation functionals, we find that error cancellations lead to remarkably good agreement between the G(0)W(0) and Kohn-Sham energies for the occupied orbitals of the adsorbed molecule.