Switching of localized surface plasmon resonance of gold nanoparticles using phase-change materials and implementation of computing functionality

Modulation of the localized surface plasmon resonance (LSPR) of gold nanospheres was investigated using a GeSbTe (GST) film as an active medium. Single-particle spectroscopy of AuNPs placed on a GST film and AuNPs on a GST/Au film (metal–insulator–metal sandwich structure) was performed, and significant switching behavior of the LSPR band due to the interaction with GST was observed. The switching mechanism was explained in terms of a change in the dielectric function of GST, and modification of the surface morphology accompanying the volume expansion and reduction of GST. To go beyond this single-particle switching functionality, we discuss the possible implementation of computing functionality that emerges from spatial correlation due to the near-field interaction of switching elements. We demonstrate that the temporal and spatial evolution of plasmon phase-change material array system can be equivalent to a cellular automata algorithm. The possibility of solving a spin-glass problem was also investigated using a coupled plasmon particle system, in which the individual coupling strengths can be modified to optimize the system so that the exact solution can be easily reached.