1D metallic states at 2D transition metal dichalcogenide semiconductor heterojunctions

TL;DR

This paper demonstrates through first-principles calculations that 2D heterojunctions of transition metal dichalcogenides host robust 1D metallic states at their interfaces due to topological polarization differences, offering a platform for studying 1D physics.

Contribution

It reveals the emergence of topologically protected 1D metallic states at TMDC heterojunctions, independent of structural details, based on polarization differences.

Findings

1D metallic states are generated at TMDC heterojunctions.

These states are topologically protected and insensitive to structural details.

The 1D metals are prone to charge- and spin-density wave instabilities.

Abstract

Two-dimensional (2D) lateral heterojunctions of transition metal dichalcogenides (TMDCs) have become a reality in recent years. Semiconducting TMDC layers in their common H -structure have a nonzero in-plane electric polarization, which is a topological invariant. We show by means of first-principles calculations that lateral 2D heterojunctions between TMDCs with a different polarization generate one-dimensional (1D) metallic states at the junction, even in cases where the different materials are joined epitaxially. The metallicity does not depend upon structural details, and is explained from the change in topological invariant at the junction. Nevertheless, these 1D metals are susceptible to 1D instabilities, such as charge- and spin-density waves, making 2D TMDC heterojunctions ideal systems for studying 1D physics.