Regensburg 2002 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 22: Postersitzung III: Syst. korr. Elektr.: Theorie II (1-15), Metall-Isol.- und Phasenüberg
änge (16-33), SL: Massivmat., Bandl., Pinning, Vortexdyn., Transport, Korngr. (34-43), Niedrigdim. Syst., Magnetotransport (44-63)

TT 22.45: Poster

Donnerstag, 14. März 2002, 14:00–17:30, A

Optical Response of the Sliding Charge Density Wave in K_0.3MoO₃ — •B. Gorshunov¹, S. Haffner¹, P. Haas¹, M. Dressel¹, B. Lommel², F. Ritter², and W. Aßmus² — ¹1. Physikalisches Institut, Universität Stuttgart — ²Physikalisches Institut, Universität Frankfurt am Main

Polarized reflection spectra of one-dimensional conductor K_0.3MoO₃ (blue bronze) are measured along the conducting chains in the far-infrared and millimeter-wave ranges down to frequency of 2 cm⁻¹ with and without applying a bias electric current. At temperatures below 180 K, in the CDW state, two resonances centered at 2 cm⁻¹ and 10 cm⁻¹ are observed, which we assign to the phason- and amplitudon-type collective excitations of the pinned CDW. If we apply a DC electric field above the threshold leading to nonlinear DC conductivity due to depinning of CDW, the optical spectra display an additional fine-structured feature at 4 cm⁻¹, in-between the phason and the amplitudon resonances. We discuss mechanisms of coupling of sliding CDW with electromagnetic radiation which can produce resonant response in the far-infrared range, in addition to the well-known narrow band noise observed in K_0.3MoO₃ at radiofrequencies.