Two-dimensional ferroelastic semiconductors in Nb2SiTe4 and Nb2GeTe4 with promising electronic properties

TL;DR

This paper predicts that single-layer Nb2SiTe4 and Nb2GeTe4 are stable 2D materials with ferroelasticity and anisotropic electronic properties, offering promising avenues for controllable electronic devices based on first-principles calculations.

Contribution

It introduces two experimentally feasible 2D ferroelastic semiconductors with tunable electronic properties, expanding beyond hypothetical structures.

Findings

Stable, exfoliable single-layer Nb2ATe4 materials.

High reversible ferroelastic strain and moderate transition energy barriers.

Anisotropic electronic and optical properties controllable via ferroelastic switching.

Abstract

Two-dimensional crystals with coupling of ferroelasticity and attractive electronic properties offer unprecedent opportunities for achieving long-sought controllable devices. But so far, the reported proposals are mainly based on hypothetical structures. Here, using first-principles calculations, we identify single-layer Nb2ATe4 (A = Si, Ge), which could be exfoliated from their layered bulks, are promising candidates. Single-layer Nb2ATe4 are found to be dynamically, thermally and chemically stable. They possess excellent ferroelasticity with high reversible ferroelastic strain and moderate ferroelastic transition energy barrier, beneficial for practical applications. Meanwhile, they harbor outstanding anisotropic electronic properties, including anisotropic carrier mobility and optical properties. More importantly, the anisotropic properties of single-layer Nb2ATe4 can be efficiently controlled through ferroelastic switching. These appealing properties combined with the experimental feasibility render single-layer Nb2ATe4 extraordinary platforms for realizing controllable devices.