Quantum spin Hall effect on the porphyrin lattice

TL;DR

This paper investigates the quantum spin Hall effect and topological phase transitions on the porphyrin lattice, revealing how different phases emerge under various symmetry conditions and connecting to known topological insulator models.

Contribution

It introduces a model of the porphyrin lattice exhibiting quantum spin Hall, quantum anomalous Hall, and insulator phases, extending understanding of topological phases in molecular lattices.

Findings

The model reduces to a topological insulator thin film in a special limit.

Explicit TRS breaking induces phase transitions among insulator, QAH, and QSH phases.

The system exhibits rich topological behavior depending on symmetry conditions.

Abstract

We study the physics of quantum spin Hall (QSH) effect and topological quantum phase transition on the porphyrin lattice. We show that in a special limit the pristine model on this lattice reduces to the usual topological insulator (TI) thin film model. By incorporating explicit time reversal symmetry (TRS) breaking interactions, we explore the topological properties of this model and show that it exhibits an ordinary insulator phase, a quantum anomalous Hall (QAH) phase, and a quantum spin Hall (QSH) phase.