Oscillatory electron phonon coupling in Pb/Si(111) deduced by temperature-dependent quantum well states

• 来源期刊: 中国物理（英文版）
• 关键词: Pb thin films photoemission quantum well states electron-phonon interactions
• 年，卷（期）: 2005,（9）
• 页码范围: 1910-1914
• 页数: 5页
• 语种: 英文

摘要

Photoemission study of atomically flat Pb films with a thickness from 15 to 24 monolayers (ML) have been performed within a temperature range 75-270K. Well-defined quantum well states (QWSs) are observed, which exhibit interesting temperature-dependent behaviours. The peak position of the QWSs shifts towards higher binding energy with increasing substrate temperature, whereas the peak width broadens linearly due to enhanced electron-phonon coupling strength (λ). An oscillatory λ with a period of 2ML is deduced. Preliminary analysis shows that the oscillation can be explained in terms of the interface induced phase variations, and is thus a manifestation of the quantum size effects.