Flat Midgap Topological Surface and Hypersurface Bands without Parameter Tuning

TL;DR

This paper extends the SSH model to higher dimensions, predicting flat topological surface bands without parameter tuning and exploring surface magnetism due to strong correlations.

Contribution

It introduces a higher-dimensional extension of the SSH model that predicts flat topological surface bands without fine-tuning and analyzes surface magnetism with Coulomb interactions.

Findings

Prediction of flat midgap surface bands without parameter tuning

Surface magnetism arising from strong correlations in 3D systems

Discussion of experimental realizations in materials and metamaterials

Abstract

The Su-Schrieffer-Heeger model is extended to the three and higher dimensional systems. Nearly or absolutely flat midgap surface and hypersurface bands are predicted based on the topological analysis, which do not require fine tuning of parameters. By adding the on-site Coulomb interaction for the three dimensional systems, we computationally show that the large difference in the band widths between the surface and the bulk leads to the strongly correlated phenomena, specifically magnetism, confined only on the surface. Possible experimental realizations in solid state materials and metamaterials are discussed.