Electron-phonon coupling on strained Ge/Si(111)-(5 × 5) surfaces
Abstract
We investigate the structural and electronic properties of strained Ge/Si(111)-(5×5) surfaces by means of scanning tunneling microscopy and high-resolution angle-resolved photoemission spectroscopy. The homogeneous (5×5) reconstructed overlayers are characterized by three electronic surface states, similar to the Si(111)-(7×7) surface. The dispersion of the dangling bond related surface state exhibits the same periodicity as that of the (5×5) reconstruction. Moreover, a careful analysis of the shape and width of this surface state provides striking evidence of electron-phonon coupling at low temperatures. By considering the spectral function within a simple Debye model, we determine both the Debye energy and the electron-phonon coupling strength. The latter value is further confirmed by analyzing the temperature-dependent phonon broadening of the dangling bond related surface state linewidth.
Domains
Physics [physics]
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