Flat Band Generation through Interlayer Geometric Frustration in Intercalated Transition Metal Dichalcogenides

TL;DR

This paper introduces a method to generate flat electronic bands in transition metal dichalcogenides via interlayer geometric frustration caused by intercalation, enabling exploration of correlated quantum phases.

Contribution

It demonstrates a general approach to induce flat bands in TMDs through intercalation, supported by experimental ARPES data and theoretical simulations.

Findings

Flat bands observed in intercalated Mn1/4TaS2 via ARPES.

Orbital character of flat bands identified through polarization ARPES.

Flat bands arise from destructive interference in hopping pathways.

Abstract

Electronic flat bands can lead to rich many-body quantum phases by quenching the electron's kinetic energy and enhancing many-body correlation. The reduced bandwidth can be realized by either destructive quantum interference in frustrated lattices, or by generating heavy band folding with avoided band crossing in Moire superlattices. Here we propose a general approach to introduce flat bands into widely studied transition metal dichalcogenide (TMD) materials by dilute intercalation. A flat band with vanishing dispersion is observed by angle-resolved photoemission spectroscopy (ARPES) over the entire momentum space in intercalated Mn1/4TaS2. Polarization dependent ARPES measurements combined with symmetry analysis reveals the orbital characters of the flat band. Supercell tight-binding simulations suggest that such flat bands arising from destructive interference between Mn and Ta on S through hopping pathways, are ubiquitous in a range of TMD families as well as for different intercalation configurations. Our findings establish a new material platform to manipulate flat band structures and explore their corresponding emergent correlated properties.