Berlin 2012 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
DS: Fachverband Dünne Schichten
DS 33: Thermoelectric materials II: Reduced dimensionality (Focused session – Organizers: Meyer, Heiliger)
DS 33.4: Talk
Thursday, March 29, 2012, 12:15–12:30, H 2032
Suppression of phonon heat conduction in undulated nanowires — Denis L. Nika1, Alexandr I. Cocemasov1, Calina I. Isacova1, Dmitrii V. Crismari1, Alexander A. Balandin2, •Vladimir M. Fomin3, and Oliver G. Schmidt3,4 — 1Lab. PIN “E. Pokatilov”, Dep. Theor. Physics, Moldova State U., MD-2009 Chisinau, Republic of Moldova — 2Nano-Device Lab., Dep. Electrical Engineering, U. California-Riverside, CA 92521 Riverside, U.S.A. — 3Institute for Integrative Nanosciences, IFW-Dresden, D-01069 Dresden, Germany — 4Material Systems for Nanoelectronics, Chemnitz University of Technology, D-09107 Chemnitz, Germany
We have theoretically demonstrated that the phonon heat flux can be significantly suppressed in Si, Si/SiO2 and Si/Ge nanowires with periodical modulation of their cross-section [undulated nanowires (UNWs)] in comparison with generic Si nanowires in a temperature range from 50 K to 400 K. The phonon energy spectra in UNWs are calculated in the framework of five-parameter Born – von Karman-type and six-parameter Valence Force Field models of lattice dynamics. A 4- to 10-fold reduction of the heat flux in UNWs is explained by the exclusion of phonon modes trapped in UNWs segments from the heat flow. Discussions with A. Rastelli and X. Zianni are gratefully acknowledged. The work was supported by the IB BMBF under Project MDA 09/007, the DFG SPP 1386 under Project RA1634/5-1 and Moldova State Project 11.817.05.10F. The work at UCR was supported by FENA.