科研之友
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摘要
We employ inelastic helium atom-surface scattering to measure the low-energy phonon dispersion along high-symmetry directions on the surface of the topological insulator Bi2Te3. Results indicate that one particular low-frequency branch experiences noticeable mode softening attributable to the interaction between Dirac fermion quasiparticles and phonons on the surface. This mode softening constitutes a renormalization of the real part of the phonon self-energy. We obtain the imaginary part, and hence lifetime information, via a Hilbert transform. In doing so, we are able to calculate an average branch-specific electron-phonon coupling constant <lambda(nu)> = 1.44.
- 出版日期2013-7-1
