Colloidal topological insulators
J. Loehr, D. de las Heras, A. Jarosz, M. Urbaniak, F. Stobiecki, A. Tomita, R. Huhnstock, I. Koch, A. Ehresmann, D. Holzinger and T. M. Fischer
Commun. Phys., 1, 4, (2018) DOI: 10.1038/s42005-017-0004-1
Full text: journal, pdf
Abstract:
Topological insulators insulate in the bulk but exhibit robust conducting edge states protected by the topology of the bulk material. Here, we design a colloidal topological insulator and demonstrate experimentally the occurrence of edge states in a classical particle system. Magnetic colloidal particles travel along the edge of two distinct magnetic lattices. We drive the colloids with a uniform external magnetic field that performs a topologically non-trivial modulation loop. The loop induces closed orbits in the bulk of the magnetic lattices. At the edge, where both lattices merge, the colloids perform skipping orbits trajectories and hence edge-transport. We also observe paramagnetic and diamagnetic colloids moving in opposite directions along the edge between two inverted patterns; the analogue of a quantum spin Hall effect in topological insulators. We present a new, robust, and versatile way of transporting colloidal particles, enabling new pathways towards lab on a chip applications.
Additional material/comments:
Download the full text for this article: journal, pdf
Related publications:
1 Topological protection of multiparticle dissipative transport (+ info)
2 Topologically protected colloidal transport above a square magnetic lattice (+ info)
3 Lattice symmetries and the topologically protected transport of colloidal particles (+ info)
4 Edge transport at the boundary between topologically equivalent lattices (+ info)
5 Hard topological versus soft geometrical magnetic particle transport (+ info)
6 Colloidal trains (+ info)
7 Simultaneous polydirectional transport of colloidal bipeds (+ info)