Regensburg 2016 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 45: Brownian Motion and Transport

DY 45.5: Vortrag

Mittwoch, 9. März 2016, 17:30–17:45, H46

Brownian Nanoparticle Racetracks — •Stefan Fringes, Michael J. Skaug, and Armin W. Knoll — IBM Research - Zurich, Rüschlikon, Switzerland

Inspired by the transport principle of molecular motors in cells, artificial Brownian motors have been studied theoretically and experimentally to achieve directed motion and sorting of particles in a fluidic environment. Ingredients of such Brownian motors are a spatially asymmetric potential landscape and unbiased external inputs driving the system out of equilibrium. In our implementation we exploit the interaction potential of charged 60 nm gold-nanospheres to like charged confining surfaces in a nanofluidic slit. We shape the asymmetric potential by patterning a 3D ratchet topography in one of the two confining surfaces using thermal scanning probe lithography. The system is driven out of equilibrium by applying a zero-mean AC-electric field. We observe a net drift of several microns per second along a direction dictated by the ratchet geometry. All relevant physical quantities can be measured in-situ enabling a parameter free comparison to theory. Our concept works on highly scaled ratchet tracks having a track width of <500 nm and a curvature down to 1 µm radius. We demonstrate the directed motion of nanoparticles in a complex racetrack and on demand transport along orthogonal racetrack directions.