Tuesday, February 14, 2012

1202.2596 (Tanmoy Das et al.)

Crossover from inelastic magnetic scattering of Cooper pairs to
spin-wave dispersion produces low-energy kink in cuprates
   [PDF]

Tanmoy Das, R. S. Markiewicz, A. Bansil
We present GW based self-energy calculations for the state of coexisting
spin-density wave and d-wave superconductivity in a series of cuprate
superconductors. In these systems, the spin resonance spectrum exhibits the
typical `hour-glass' form, whose upward and downward dispersion branches come
from the gapped spin-wave and magnetic scattering of Cooper pairs,
respectively. We show that the crossover between these two different dispersion
features leads to an abrupt change in slope in the quasiparticle self-energy,
and hence the low-energy kink commences in the single-particle quasiparticle
spectrum. The calculated electron-bosonic coupling strength agrees well with
experimental data as a function of temperature, doping and material. The
results demonstrate that the electronic correlations dominate the quasiparticle
spectra of cuprates near the low-energy kink, suggesting a relatively smaller
role for phonons in this energy range.
View original: http://arxiv.org/abs/1202.2596

No comments:

Post a Comment