科研之友
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摘要
We have developed a new approach, starting from the Frohlich Hamiltonian and by means of the unitary transformation with the perturbation treatment, to deal with the momentum-dependent spectral functions (MDSF) of electron-phonon coupling system. The approach takes care of the fact that only those electrons near the Fermi surface within a layer of width omega(ph) (phonon frequency) are scattered by phonons strongly. Our results show that the MDSF is mainly composed of two parts: the zero-phonon part and the one-phonon one. When the bare electron energy epsilon(k) is close to the Fermi energy E(F), parallel to epsilon(k)-E(F)parallel to similar or equal to omega(ph), the one-phonon part is quite significant and the MDSF shows a two-headed peak. However, for parallel to epsilon(k)-E(F)parallel to >omega(ph), the one-phonon part disappears gradually and the MDSF shows a single broad peak. Our calculation for MDSF is qualitatively in agreement with recent measurement of angle-resolved photoemission spectroscopy on the Be(0001) surface and Bi(2)Sr(2)CaCu(2)O(8). Besides, the two-headed structure of MDSF indicates the "hybridization" between electrons and phonons.
- 出版日期2007-9
- 单位上海交通大学
