Disorder-induced broadening of transverse acoustic phonons in SixGe1-x mixed crystals

0101894 - UJF-V 20043084 RIV NL eng J - Článek v odborném periodiku
Beraud, A. - Kulda, Jiří - Yonenaga, I. - Foret, M. - Salce, B. - Courtens, E.
Disorder-induced broadening of transverse acoustic phonons in SixGe1-x mixed crystals.
[Rozšíření příčných akustických fononů ve smíšených krystalech Si(x)Ge(1-x) vyvolané neuspořádaností.]
Physica B-Condensed Matter. Roč. 350, č. 1 (2004), s. 254-257. ISSN 0921-4526. E-ISSN 1873-2135
Grant CEP: GA AV ČR KSK1010104
Klíčová slova: disordered crystals * acoustic branches
Kód oboru RIV: BG - Jaderná, atomová a mol. fyzika, urychlovače
Impakt faktor: 0.679, rok: 2004

Inelastic neutron-scattering measurements of the dispersion and width of transverse acoustic branches are reported for SixGe1-x, particularly for x = 0.51. These alloys form high-quality single crystals. They are strongly disordered dynamically owing to the large Ge/Si mass ratio. This allows to study in function of disorder (x) the relations between the inhomogeneous broadening of acoustic waves, the Boson peak, and low-temperature thermal anomalies common to glasses. For x less than or equal to 0.51 we find no boson peak, apparently no plateau in the thermal conductivity, but at large x a Rayleigh law on the phonon width, Gamma proportional to Q(4), where Q is the scattering vector

Disperze a šířka příčných akustických fononů byly měřeny inelastickým rozptylem neutronů.
Trvalý link: http://hdl.handle.net/11104/0009275