Fluctuations and order in a one-dimensional system. A spectroscopical study of the Peierls transition in K 2 Pt ( CN ) 4 Br 0.3 ·3( H 2 O)

摘要: Using optical spectroscopy in the energy range 1 meV-6 eV as a tool we have studied Peierls transition ${\mathrm{K}}_{2}$Pt${(\mathrm{CN})}_{4}$${\mathrm{Br}}_{0.3}$\ifmmode\cdot\else\textperiodcentered\fi{}3(${\mathrm{H}}_{2}$O). We find pseudogap at 0.2 room temperature which transforms into real gap $\mathrm{T}\ensuremath{\rightarrow}0$ without significantly changing energy. From this infer that although no long-range order exists rms parameter has already reached its zero value. At $T\ensuremath{\approx}0$ strong structure $\ensuremath{\sigma}(\ensuremath{\omega})$ $\ensuremath{\omega}\ensuremath{\sim}15$ ${\mathrm{cm}}^{\ensuremath{-}1}$ is assigned to an oscillation of pinned charge-density wave (CDW). A simple phenomenological model allows us estimate contribution thermally unpinned CDW dc conductivity $Tg0$. conclude 50% or less total conductivity.