Objective
This project will explore the mechanisms of interaction of phonons in solids with an extremely high chemical, structural and isotopical purity and also with tailor-made isotopic compositions. The first step is the fabrication of the single crystals of germanium containing 99.9 % of 70Ge and the study of its thermal conductivity as a function of the temperature, the direction of heat flux and the density of injected charge carriers. In a later stage, 28Si will be prepared and its thermal conductivity will be studied under the conditions mentioned above.
The project aims to reach the record absolute value of the thermal conductivity (because of the high isotopical purification of the sample) and on the basis of the comparison with the theoretical calculations, to solve very delicate questions concerning the interactions of phonons with each other and with various quasi-particles of the crystal.
Using the same crystals the project will also study the isotopic dependence of the optical properties of solids. Among other things the effect of isotope concentration and disorder on electronic and vibronic excitations will be investigated. Luminescence and Raman scattering will be used in order to characterise the single crystals so obtained. Very accurate measurements of the lattice parameter will also be carrried out.
Topic(s)
Call for proposal
Data not availableFunding Scheme
Data not availableCoordinator
D-70569 STUTTGART
Germany