Vertex Corrections for Positive-Definite Spectral Functions of Simple Metals
Pavlyukh, Y., Uimonen, A.-M., Stefanucci, G., & van Leeuwen, R. (2016). Vertex Corrections for Positive-Definite Spectral Functions of Simple Metals. Physical Review Letters, 117 (20), 206402. doi:10.1103/PhysRevLett.117.206402
Published inPhysical Review Letters
© 2016 American Physical Society. Published in this repository with the kind permission of the publisher.
We present a systematic study of vertex corrections in a homogeneous electron gas at metallic densities. The vertex diagrams are built using a recently proposed positive-definite diagrammatic expansion for the spectral function. The vertex function not only provides corrections to the well known plasmon and particle-hole scatterings, but also gives rise to new physical processes such as the generation of two plasmon excitations or the decay of the one-particle state into a two-particle–one-hole state. By an efficient Monte Carlo momentum integration we are able to show that the additional scattering channels are responsible for a reduction of the bandwidth, the appearance of a secondary plasmon satellite below the Fermi level, and a substantial redistribution of spectral weights. The feasibility of the approach for first-principles band-structure calculations is also discussed.