Dresden 2011 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

TT: Fachverband Tiefe Temperaturen

TT 3: CE: Charge Density Wave \& Peierls Instability

TT 3.5: Talk

Monday, March 14, 2011, 11:45–12:00, HSZ 304

Extended Phonon Collapse in the Charge-Density-Wave Compound NbSe₂ — •Frank Weber^1,2, Stephan Rosenkranz², John-Paul Castellan², Raymond Osborn², Roland Hott¹, Rolf Heid¹, Klaus-Peter Bohnen¹, Takeshi Egami³, Ayman Said⁴, and Dmitry Reznik^1,5 — ¹Karlsruhe Institute of Technology, Institute of Solid State Physics, P. O. Box 3640, D-76021 Karlsruhe, Germany — ²Materials Science Division, Argonne National Laboratory, Argonne, Illinois, 60439, USA — ³Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee, 37996, USA — ⁴Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, 60439, USA — ⁵Department of Physics, University of Colorado at Boulder, Boulder, Colorado, 80309, USA

We investigated the phonon softening in the charge density wave compound NbSe₂ using the high-resolution hard inelastic x-ray scattering beamline 30-ID-C at the Advanced Photon Source, Argonne National Laboratory. The acoustic Σ₁ phonon branch was measured from the zone center Γ to the M point at temperatures between 250 K and 8 K across the CDW transition at T_CDW = 33 K. Density functional theory calculations for the lattice dynamical properties which predict an extended phonon breakdown are used to analyze the detailed nature of the softening phonon branch. Work supported by US DOE BES-DMS DE-AC02-06CH11357.