АКУСТИЧЕСКИЕ ФОНОНЫ В Si/Ge SUPRA-КРИСТАЛЛЕ

Денис НИКА, Евгений ПОКАТИЛОВ, Надежда ЗИНЧЕНКО Лаборатория физики многослойных структур и молекулярного магнетизма

Abstract

In the presented article we relate on the theoretical investigation of acoustic phonon properties in Si/Ge threedimensionally ordered quantum dots superlattices (supra-crystals). Our calculations of the acoustic phonon energy spectra and phonon dispersions were performed in the framework of the face-centered cubic cell molecular-dynamic model. We have investigated the dependencies of phonon density of states and phonon group velocity on the phonon energy and have established that the average phonon velocity is close to zero in the wide range of phonon energies hω >10 meV. The obtained results allow us to predict the extremely low value of the lattice thermal conductivity in supra-crystals and correspondingly extremely high value of the thermoelectric figure of merit ZT