1 research outputs found
Collective modes in the charge-density wave state of KMoO: The role of long-range Coulomb interactions revisited
We re-examine the effect of long-range Coulomb interactions on the collective
amplitude and phase modes in the incommensurate charge-density wave ground
state of quasi-one-dimensional conductors. Using an effective action approach
we show that the longitudinal acoustic phonon protects the gapless linear
dispersion of the lowest phase mode in the presence of long-range Coulomb
interactions. Moreover, in Gaussian approximation amplitude fluctuations are
not affected by long-range Coulomb interactions. We also calculate the
collective mode dispersions at finite temperatures and compare our results with
the measured energies of amplitude and phase modes in KMoO. With
the exception of the lowest phase mode, the temperature dependence of the
measured mode energies can be quantitatively described within a multi-phonon
Fr\"{o}hlich model neglecting long-range Coulomb interactions