Topological phase transition and the effect of Hubbard interaction on the one-dimensional topological Kondo insulator

TL;DR

This study investigates how Hubbard interactions and Kondo coupling influence the topological phases of a one-dimensional topological Kondo insulator, revealing conditions under which the symmetry-protected topological phase is destroyed.

Contribution

It provides a detailed numerical analysis of the interplay between Hubbard interaction and Kondo coupling in topological Kondo insulators, highlighting the phase transition mechanisms.

Findings

Hubbard interaction alone does not destroy the SPT phase.

Kondo coupling can induce a topological phase transition.

Charge sector correlations diverge at the transition.

Abstract

The effect of a local Kondo coupling and Hubbard interaction on the topological phase of the one-dimensional topological Kondo insulator (TKI) is numerically investigated using the infinite matrix-product state density-matrix renormalization group algorithm. The groundstate of the TKI is a symmetry-protected topological (SPT) phase protected by inversion symmetry. It is found that on its own, the Hubbard interaction that tends to force fermions into a one-charge per site order is insufficient to destroy the SPT phase. However when the local Kondo Hamiltonian term that favors a topologically trivial groundstate with a one-charge per site order is introduced, the Hubbard interaction assists in the destruction of the SPT phase. This topological phase transition occurs in the charge sector where the correlation length of the charge excitation diverges while the correlation length of the spin excitation remains finite. The critical exponents, central charge and the phase diagram separating the SPT phase from the topologically trivial phase are presented.