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Personal page Olof Andersson

Ratchet structures for energy harvesting

My name is Olof and I work as a PhD student in the science group Complex Materials and Devices, CoMaDe. I am 27 years old and come from Lycksele, Sweden. I finished my master programme in applied physics and electrical engineering, specialization in Nano and Material Physics, fall 2014 at Linköping University.

 In the CoMaDe group I am investigating ratchet structures for potential use in energy harvesting. A ratchet is a component that consists of a series of asymmetric parts, and is lacking inversion symmetry. Thus, the ratchet generate an asymmetric potential landscape. Ratchets are driven by a (usually periodic) force which is rectified by the asymmetry and a net flow of particles in one direction can be achieved. Any device that fulfills these criteria can be called a ratchet which give high degrees of freedom in construction: the asymmetry may originate from physical or induced potentials, and the particles to be transported may be varied widely.

 One example is an on/off ratchet which generates a sawtooth potential in its “on”-state and a plane potential in its “off”-state. Here, the idea is that particles are distributed sharply centered in the potential wells. When the potential is off, the particles will diffuse and distribute over a wider area. Consequently, when the potential is turned on again, forming the sawtooth potential, the particles that had diffused over an edge will drift to the bottom of the well in the contemporary sawtooth. Thus, a net motion is achieved by periodically creating and removing asymmetrical sawtooth potentials. [1]   

Figure 1. The operation of an on/off-ratchet [1]

[1] Appl. Phys. Lett. 102, 073104 (2013) doi: 10.1063/1.4793198 ;

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Last updated: 09/17/15