Real-time observation of nanoscale topological transitions in epitaxial PbTe/CdTe heterostructures
The almost completely immiscible PbTe/CdTe heterostructure has recently become a prototype system for self-organized quantum dot formation based on solid-state phase separation. Here, we study by real-time transmission electron microscopy the topological transformations of two-dimensional PbTe-epila...
Saved in:
Published in | APL materials Vol. 2; no. 1; pp. 012105 - 012105-8 |
---|---|
Main Authors | , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
AIP Publishing LLC
01.01.2014
|
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | The almost completely immiscible PbTe/CdTe heterostructure has recently become a prototype system for self-organized quantum dot formation based on solid-state phase separation. Here, we study by real-time transmission electron microscopy the topological transformations of two-dimensional PbTe-epilayers into, first, a quasi-one-dimensional percolation network and subsequently into zero-dimensional quantum dots. Finally, the dot size distribution coarsens by Ostwald ripening. The whole transformation sequence occurs during all stages in the fully coherent solid state by bulk diffusion. A model based on the numerical solution of the Cahn-Hilliard equation reproduces all relevant morphological and dynamic aspects of the experiments, demonstrating that this standard continuum approach applies to coherent solids down to nanometer dimensions. As the Cahn-Hilliard equation does not depend on atomistic details, the observed morphological transformations are general features of the model. To confirm the topological nature of the observed shape transitions, we developed a parameter-free geometric model. This, together with the Cahn-Hilliard approach, is in qualitative agreement with the experiments. |
---|---|
ISSN: | 2166-532X 2166-532X |
DOI: | 10.1063/1.4859775 |