Defect dynamics of thermal phonons in two-dimensional dusty plasma crystals

Wei-Shuo Lo^1*, Lin I¹

¹Department of Physics and Center for Complex Systems, National Central University, Jhongli, Taiwan

* Presenter:Wei-Shuo Lo, email:loweishuo@gmail.com

Topological defects (TDs) are crucial to characterize the ordering and disordering of extended systems such as crystals, liquid crystals, and fluids. We recently reported thermally excited multiscale vortical phonons—coherent excitations propagating as swirls—in two-dimensional (2D) dusty plasma crystals under low gaseous pressure. This work further identifies the associated TDs, which carry conjugate topological charges (+1 and -1) at the cores of these vortices and saddles, and explores their spatiotemporal dynamics. In low‑frequency modes, ±1 defect pairs nucleate spontaneously, propagate, and annihilate in xyt space, establishing a finite lifetime for each TD and conservation of topological charge. Following individual vortex cores, the local vorticity increases after nucleation and decays prior to annihilation. Moreover, defects with the same charge tend to repel each other, while those with opposite charges are mutually attractive.

Keywords: Topological defects, Thermal phonons , Dusty plasma crystals