A spectral function tour of electron-phonon coupling outside the Migdal limit

Details A spectral function tour of electron-phonon coupling outside the Migdal limit A spectral function tour of electron-phonon coupling outside the Migdal limit

2011-02-17

arxiv.org/abs/1102.3716v2

Phys. Rev. B 84, 085126 (2011)

Physics

Condensed Matter

Strongly Correlated Electrons

15 pages, 11 figures. High resolution available here: http://www.physics.ubc.ca/~quantmat/ARPES/PUBLICATIONS/Articles/sf_tour.

Scientific paper

10.1103/PhysRevB.84.085126

We simulate spectral functions for electron-phonon coupling in a filled band system - far from the asymptotic limit often assumed where the phonon energy is very small compared to the Fermi energy in a parabolic band and the Migdal theorem predicting 1+lambda quasiparticle renormalizations is valid. These spectral functions are examined over a wide range of parameter space through techniques often used in angle-resolved photoemission spectroscopy (ARPES). Analyzing over 1200 simulations we consider variations of the microscopic coupling strength, phonon energy and dimensionality for two models: a momentum-independent Holstein model, and momentum-dependent coupling to a breathing mode phonon. In this limit we find that any `effective coupling', lambda_eff, inferred from the quasiparticle renormalizations differs from the microscopic dimensionless coupling characterizing these Hamiltonians, lambda, and could drastically either over- or under-estimate it depending on the particular parameters and model. In contrast, we show that perturbation theory retains good predictive power for low coupling and small momenta, and that the momentum-dependence of the self-energy can be revealed via the relationship between velocity renormalization and quasiparticle strength. Additionally we find that (although not strictly valid) it is often possible to infer the self-energy and bare electronic structure through a self-consistent Kramers-Kronig bare-band fitting; and also that through lineshape alone, when Lorentzian, it is possible to reliably extract the shape of the imaginary part of a momentum-dependent self-energy without reference to the bare-band.

Affiliated with

Also associated with

No associations

Rating

A spectral function tour of electron-phonon coupling outside the Migdal limit does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with A spectral function tour of electron-phonon coupling outside the Migdal limit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A spectral function tour of electron-phonon coupling outside the Migdal limit will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-210990