1. Collective modes in the charge-density wave state of K$_{0.3}$MoO$_3$: The role of long-range Coulomb interactions revisited
- Author
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Hansen, Max O., Palan, Yash, Hahn, Viktor, Thomson, Mark D., Warawa, Konstantin, Roskos, Hartmut G., Demsar, Jure, Pientka, Falko, Tsyplyatyev, Oleksandr, and Kopietz, Peter
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
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 K$_{0.3}$MoO$_3$. 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 for generic electron-phonon interactions neglecting long-range Coulomb interactions.
- Published
- 2023
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