Dirac States in an Inclined Two-Dimensional Su-Schrieffer-Heeger Model

TL;DR

This paper introduces a tunable two-dimensional Su-Schrieffer-Heeger model that hosts Dirac points protected by symmetry, undergoing topological phase transitions into insulators or semimetals, with potential experimental realizations.

Contribution

It presents a novel inclined 2D SSH model with tunable Dirac points and analyzes the associated topological phase transitions and boundary states.

Findings

Dirac points are protected by space-time inversion symmetry.

Dirac points are tunable and not fixed at high-symmetry points.

Merging Dirac points induces topological phase transitions.

Abstract

We propose to realize Dirac states in an inclined two-dimensional Su-Schrieffer-Heeger model on a square lattice. We show that a pair of Dirac points protected by space-time inversion symmetry appear in the semimetal phase. The locations of these Dirac points are not pinned to any high-symmetry points of the Brillouin zone but are tunable through parameter modulations. Interestingly, the merging of two Dirac points undergoes a topological phase transition that leads to either a weak topological insulator or a nodal-line semimetal. We provide a systematic analysis of these topological phases from both bulk and boundary perspectives combined with symmetry arguments. We also discuss feasible experimental platforms to realize our model.