Speaker
Description
Topological defects (TDs) arise almost inevitably during phase transitions that involve continuous symmetry breaking. Owing to their topological nature, their essential characteristics are largely independent of microscopic system details, leading to a wide range of universal behaviors. In this work, we present a numerical investigation of TDs in effectively two-dimensional closed soft films with in-plane orientational order, such as liquid crystalline shells and biological membranes. We introduce the Effective Topological Charge Cancellation mechanism, which governs the localized spatial organization of TDs and describes the formation of defect–antidefect pairs on curved surfaces and in the presence of relevant inhomogeneities (e.g., nanoparticles). We define an effective topological charge, incorporating contributions from real, virtual, and curvature-induced (smeared) charges within surface patches characterized by different spatially averaged values of Gaussian curvature. Our results reveal a strong tendency for effective topological charge to go to zero in regions composed of patches with significantly different values of Gaussian curvature. For cases where effective topological charge does not equal to zero, we estimate a critical depinning threshold for defect–antidefect pair formation using an electrostatic analogy.