Motion of particles and molecules in feedback controlled dynamic temperature fields
Par Frank Cichos, Molecular Nano-Phononics, Peter-Debye-Institut für Physik der weichen Materie, Universität Leipzig
Mardi 12 Février, 14h00, Salle des séminaires (215), 2ème étage, Bâtiment A4N
Abstract :
The generation of localized temperature gradients is accompanied by new fundamental physics and also provides new tools for the control of molecules, particles or more complex matter in solution.
We describe experiments, which use metal nano- and microstructures as optically pumped heat sources. Heat flowing from these structures along solid/liquid interfaces sets liquids into motion. With the help of such thermo-osmotic creeps flows, we are able to trap particles and single molecules suspended in liquids without any external forces. Combined with optical feedback almost arbitrary effective potential landscapes may be created in which the temperature mimics the role of a potential.
Finally, when merging heat sources and passive particles/molecules new active materials are formed, which represent microscopic engines and yield a model system for self-propelled biological objects. Applying feedback mechanisms to those structures opens new pathways of self-organization due to virtual information based interactions as present in flocks of birds or school of fish.