Domain Formation Driven by the Entropy of Topological Edge Modes

• Main Authors: Oreg, Y. (Author), Shavit, G. (Author)
• Format: Article
• Language: English
• Published: American Physical Society 2022
• Subjects: Discrete symmetry; Domain formation; Domain structure; Domain walls; Entropy; Graphene; Interacting system; Order parameter; Symmetry breakings; Thermal transitions; Topological phase; Topology; Uniform phase; Weak disorder
• Online Access: View Fulltext in Publisher

 In this Letter we study interacting systems with spontaneous discrete symmetry breaking, where the degenerate symmetry-broken states are topologically distinct gapped phases. Edge modes appear at domain walls between the two topological phases. In the presence of a weak disorder field conjugate to the order parameter, we find that the entropy of the edge modes drives a thermal transition between a gapped uniform phase and a phase with a disorder-induced domain structure. We characterize this transition using a phenomenological Landau functional, and corroborate our conclusions with a concrete microscopic model. Finally, we discuss the possibilities of experimental signatures of this phase transition, and propose graphene-based moiré heterostructures as candidate materials in which such a phase transition can be detected. © 2022 American Physical Society.