中国物理B ›› 2013, Vol. 22 ›› Issue (9): 96801-096801.doi: 10.1088/1674-1056/22/9/096801
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宋博群, 潘理达, 杜世萱, 高鸿钧
Song Bo-Qun (宋博群), Pan Li-Da (潘理达), Du Shi-Xuan (杜世萱), Gao Hong-Jun (高鸿钧)
摘要: In order to understand the Kondo effect observed in molecular systems, first-principles calculations have been widely used to predict the ground state properties of molecules on metal substrates. In this work, the interaction and the local magnetic moments of magnetic molecules (3d-metal phthalocyanine and tetraphenylporphyrin molecules) on noble metal surfaces are investigated based on the density functional theory. The calculation results show that the dz2 orbital of the transition metal atom of the molecule plays a dominant role in the molecule-surface interaction and the adsorption energy exhibits a simple declining trend as the adsorption distance increases. In addition, the Au(111) surface generally has a weak interaction with the adsorbed molecule compared with the Cu(111) surface and thus serves as a better candidate substrate for studying the Kondo effect. The relation between the local magnetic moment and the Coulomb interaction U is examined by carrying out the GGA+U calculation according to Dudarev’s scheme. We find that the Coulomb interaction is essential for estimating the local magnetic moment in molecule-surface systems, and we suggest that the reference values of parameter U are 2 eV for Fe and 2-3 eV for Co.
中图分类号: (Adsorbate structure (binding sites, geometry))