Phonons in slow motion: dispersion relations in ultrathin Si membranes.
We report the changes in dispersion relations of hypersonic acoustic phonons in free-standing silicon membranes as thin as ∼8 nm. We observe a reduction of the phase and group velocities of the fundamental flexural mode by more than 1 order of magnitude compared to bulk values. The modification of the dispersion relation in nanostructures has important consequences for noise control in nano- and microelectromechanical systems (MEMS/NEMS) as well as opto-mechanical devices.
Catalan Institute of Nanotechnology, Campus UAB, 08193 Bellaterra (Barcelona), Spain.
John
J
Cuffe
Emigdio
E
Chávez
Andrey
A
Shchepetov
Pierre-Olivier
PO
Chapuis
El Houssaine
el H
El Boudouti
Francesc
F
Alzina
Timothy
T
Kehoe
Jordi
J
Gomis-Bresco
Damian
D
Dudek
Yan
Y
Pennec
Bahram
B
Djafari-Rouhani
Mika
M
Prunnila
Jouni
J
Ahopelto
Clivia M
CM
Sotomayor Torres