2003/04/22 by J. P. Hague · 28 citations
Mathematics · Physics and Astronomy · #Advanced Condensed Matter Physics #Condensed matter physics #Dispersion (optics) #Dispersion relation #Electron #Mathematics #Phonon #Physics #Physics of Superconductivity and Magnetism #Quantum electrodynamics #Quantum mechanics #Superconductivity in MgB2 and Alloys #Vertex (graph theory) #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1088/0953-8984/15/17/309
published in Journal of Physics Condensed Matter 15(17), 2535-2550 (IOP Publishing) · I am posting reprints of the final submitted versions of previous articles to improve access. Here ARPES "kinks" are discussed. Article was published in 2003. 17 pages, 9 figures
openalex publication_date 2003/04/22 · arxiv created 2007/02/24 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
I apply the newly developed dynamical cluster approximation (DCA) to the calculation of the electron and phonon dispersions in the two-dimensional Holstein model. In contrast to previous work, the DCA enables the effects of spatial fluctuations (non-local corrections) to be examined. Approximations neglecting and incorporating lowest-order vertex corrections are investigated. I calculate the phonon density of states, the renormalized phonon dispersion, the electron dispersion and electron spectral functions. I demonstrate how vertex corrections stabilize the solution, stopping a catastrophic softening of the (π, π) phonon mode. A kink in the electron dispersion is found in the normal state along the (ζ, ζ) symmetry direction in both the vertex- and non-vertex-corrected theories for low phonon frequencies, corresponding directly to the renormalized phonon frequency at the (π, 0) point. This kink is accompanied by a sudden drop in the quasi-particle lifetime. Vertex and non-local corrections enhance the effects at large bare phonon frequencies.