Interaction-induced phase transitions at topological quantum criticality of an extended Su-Schrieffer-Heeger model

TL;DR

This study numerically investigates how interactions induce phase transitions in an extended SSH model at topological quantum critical points, revealing that interactions can drive trivial phases into nontrivial insulators.

Contribution

It demonstrates the interaction-driven topological phase transitions at quantum critical points in an extended SSH model, highlighting the complex role of interactions in topological phase stability.

Findings

Interaction induces topological phase transitions between trivial and nontrivial phases.

Trivial insulator phases can be driven into nontrivial insulators by interactions.

Stability of trivial phases diminishes at multicritical points.

Abstract

Topological phases at quantum criticality attract much attention recently. Here we numerically study the interaction-induced phase transitions at around the topological quantum critical points of an extended Su-Schrieffer-Heeger (SSH) chain with next-nearest-neighbor hopping. This extended SSH model shows topological phase transitions between the topologically trivial and nontrivial critical phases when interaction is absent. So long as the interaction terms are turned on, the topologically nontrivial (trivial) critical phases are driven into topologically nontrivial (trivial) insulator phases with finite energy gaps. Particularly, we find the trivial insulator phase is further driven to the nontrivial insulator phase, through interaction-induced topological phase transition, although interaction generally is harmful to nontrivial topology. The stability of trivial insulator phase against interaction tends to vanish at the multicritical point that separates the trivial and nontrivial critical phases. Our work provides a concrete example for manifesting the impact of interaction on topological quantum criticality.