ISSN:
1434-6036
Keywords:
PACS. 63.20.Kr Phonon-electron and phonon-phonon interactions - 71.38.+i Polarons and electron-phonon interactions - 74.20.Mn Nonconventional mechanisms (spin fluctuations, polarons and bipolarons, resonating valence bond model, anyon mechanism, marginal Fermi liquid, Luttinger liquid, etc.)
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract: In the theory of nonadiabatic superconductivity several features are governed by the electron-phonon vertex correction which has a complex structure both in momentum and frequency. We derive a physical interpretation of such nonadiabatic effects that permits to link them to specific material properties. We show how the nonadiabatic vertex correction can be decomposed into two terms with different physical origins. In particular, the first term describes the lattice polarization induced by the electrons and it is essentially a single-electron process whereas the second term is governed by the particle-hole excitations due to the exchange part of the phonon-mediated electron-electron interaction. We show that by weakening the influence of the exchange interaction the vertex takes mostly positive values giving rise to an enhanced effective coupling in the scattering with phonons. This weakening of the exchange interaction can be obtained by lowering the density of the electrons, or by considering only long-ranged (small q) electron-phonon couplings.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s100510050852
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