https://doi.org/10.1140/epjb/e2016-60799-9
Regular Article
Generalized Drude scattering rate from the memory function formalism: an independent verification of the Sharapov-Carbotte result
1 Physical Research Laboratory,
Navrangpura,
380009
Ahmedabad,
India
2 Indian Institute of Technology
382424
Gandhinagar,
India
a
e-mail: pankaj@prl.res.in
Received:
8
October
2015
Received in final form:
15
December
2015
Published online:
17
February
2016
An explicit perturbative computation of the Mori’s memory function was performed by Götze and Wölfle (GW) to calculate generalized Drude scattering (GDS) rate for the case of electron-impurity and electron-phonon scattering in metals by assuming constant electronic density of states at the Fermi energy. In the present investigation, we go beyond this assumption and extend the GW formalism to the case in which there is a gap around the Fermi surface in electron density of states. The resulting GDS is compared with a recent one by Sharapov and Carbotte (SC) obtained through a different route. We find good agreement between the two at finite frequencies. However, we find discrepancies in the dc scattering rate. These are due to a crucial assumption made in SC namely ω ≫ | Σ(ϵ + ω) − Σ∗(ϵ) |. No such high frequency assumption is made in the memory function based technique.
Key words: Solid State and Materials
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2016