Quantum-well states with image state character for Pb overlayers on Cu(111)

Article

关键词: FEMTOSECOND ELECTRON DYNAMICS;    POTENTIAL STATES;    METAL INTERFACES;    SURFACE-STATES;    THIN METAL;    PHOTOEMISSION;    EXCITATIONS;    LIFETIMES;    FILMS;    ENERGIES;   

DOI  :  10.1103/PhysRevB.86.075434

来源: SCIE

【 摘 要 】

We study theoretically the quantum well states (QWSs) localized in Pb overlayers on Cu(111) surface. Particular emphasis is given to the states with energies close to the vacuum level. Inclusion of the long-range image potential tail into the model potential description of the system allows us to show the effect of hybridization between QWSs and image potential states (ISs). The particle-in-a-box energy sequence characteristic for QWSs evolves into the Rydberg series converging towards the vacuum level. The electron density of the corresponding states is partially moved from inside the metal overlayer into the vacuum. The decay rates due to the inelastic electron-electron scattering decrease with increasing energy, opposite to conventional QWSs and similar to the ISs. Many-body and wave packet propagation calculations of the inelastic decay rates are supplemented by simple analysis based on the phase accumulation model and wave-function penetration approximation. This allows an analytical description of the dependence of the QWS/ISs hybridization on different parameters and, in particular, on the overlayer thickness.

【 授权许可】

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