Modulating the molecular orbitals of matter through tailoring at the nanoscale using a topographic interface to enable versatile colloidal current devices

Abstract

In this study, we present a novel approach for colloidal particle manipulation that leverages the topographic effect generated by micro-hills and surface gradients around a micro-magnet. We demonstrate that the magnetic landscape, or matter orbital, created by periodically arranged circular micro-magnets induces a symmetric orbit of magnetic particle flow under a rotating magnetic field. However, the presence of irregular topographic structures on the surface can disrupt the intended control of particle manipulation. By controlling the distance between the source of the driving force and the target particles with sub-nanometer precision on the surface morphology, we can break the symmetry of the energy distribution and distort the symmetric orbit of colloidal flow. This can be achieved without changing the driving force, but by modifying the symmetry in the energy landscape at the switching point. Furthermore, we show that the enhancement of the magnetic effect of the micro-magnet array can restore the symmetry of the orbit. We also demonstrate the application of this technique on on-chip-based devices configured by symmetry control, showcasing its potential for selective manipulation, trapping, recovery, and altering the direction of colloidal particles using a time-dependent magnetic field. This novel approach could find applications in precise lab-on-a-chip systems where the topographic effect is required as an additional variable without disrupting the existing control methods. Overall, our findings highlight the potential of this innovative approach for precise micro-particle manipulation in biomedical and lab-on-a-chip applications, offering new possibilities for manipulating particles with intricate topographic structures.