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Ultrafast study of phonon transport in isotopically controlled semiconductor nanostructures
Author(s) -
Issenmann Daniel,
Eon Soizic,
Bracht Hartmut,
Hettich Mike,
Dekorsy Thomas,
Buth Gernot,
Steininger Ralph,
Baumbach Tilo,
Lundsgaard Hansen John,
Nylandsted Larsen Arne,
Ager Joel W.,
Haller Eugene E.,
Plech Anton
Publication year - 2016
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201532462
Subject(s) - phonon , femtosecond , materials science , brillouin zone , silicon , germanium , scattering , thermal conductivity , semiconductor , spectroscopy , condensed matter physics , phonon scattering , ultrashort pulse , optics , optoelectronics , laser , physics , quantum mechanics , composite material
Isotopically modulated silicon and germanium multilayers are analyzed by means of femtosecond spectroscopy and pulsed X‐ray scattering for determining thermal conductivity and phonon modes. Isotopic modulation decreases thermal conductivity stronger than expected from a band bending model in the coherent phonon transport regime, in particular for silicon. Femtosecond spectroscopy and X‐ray scattering resolve zone‐folded vibration modes, which are located at the edge of the new, smaller Brillouin zone due to the multilayer periodicity. These modes can contribute to the reduction of thermal conductivity by Umklapp processes within the zone‐folded mini‐bands. Color‐coded increase in ultrafast X‐ray scattering in vicinity to the mini‐zone boundary of a germanium multilayer.