Generalized Aubry-Andr\'e-Harper model with p-wave superconducting pairing

TL;DR

This paper explores a generalized Aubry-Andre9-Harper model with p-wave superconducting pairing, revealing phase transitions between extended, localized, and various topological phases in quasiperiodic systems.

Contribution

It introduces a generalized AAH model with modulated hopping and potential, analyzing its phase diagram and topological properties, especially under different periodicity conditions.

Findings

In incommensurate case, the critical region is reduced, facilitating transition from extended to localized states.

In the commensurate case, three phases are identified: trivial, SSH-like topological, and Kitaev-like topological.

The model serves as a platform to study phase transitions between extended, localized, and topological states.

Abstract

We investigate a generalized Aubry-Andr\'e-Harper (AAH) model with p-wave superconducting pairing. Both the hopping amplitudes between the nearest neighboring lattice sites and the on-site potentials in this system are modulated by a cosine function with a periodicity of $1/\alpha$. In the incommensurate case [$\alpha=(\sqrt{5}-1)/2$], due to the modulations on the hopping amplitudes, the critical region of this quasiperiodic system is significantly reduced and the system becomes more easily to be turned from extended states to localized states. In the commensurate case ($\alpha = 1/2$), we find that this model shows three different phases when we tune the system parameters: Su-Schrieffer-Heeger (SSH)-like trivial, SSH-like topological, and Kitaev-like topological phases. The phase diagrams and the topological quantum numbers for these phases are presented in this work. This generalized AAH model combined with superconducting pairing provides us with a useful testfield for studying the phase transitions from extended states to Anderson localized states and the transitions between different topological phases.