First-Principles Mapping of the Electronic Properties of Two-Dimensional Materials for Strain-Tunable Nanoelectronics

TL;DR

This study uses first-principles calculations to map the electronic properties of various 2D materials under non-uniform strain, providing insights for strain engineering in nanoelectronic device development.

Contribution

It introduces a comprehensive strain mapping approach for 2D materials, revealing new regimes of electronic behavior and emphasizing the need for generalized analysis beyond standard strain directions.

Findings

${eta}$-Te exhibits unique localization of band edges under non-uniform strain.

Strain mapping offers deeper understanding of band gap modulation in 2D materials.

${ m ext{alpha}}$-Te and ${ m ext{beta}}$-Te are more elastic than other 2D compounds.

Abstract

Herein, we demonstrate that first-principles calculations can be used for mapping electronic properties of two-dimensional (2d) materials with respect to non-uniform strain. By investigating four representative single-layer 2d compounds with different symmetries and bonding characters, namely 2d-${MoS_2}$, phosphorene, ${\alpha}$-Te, and ${\beta}$-Te, we reveal that such a mapping can be an effective guidance for advanced strain engineering and development of strain-tunable nanoelectronics devices, including transistors, sensors, and photodetectors. Thus, we show that ${\alpha}$-Te and ${\beta}$-Te are considerably more elastic compared to the 2d compounds with strong chemical bonding. In case of ${\beta}$-Te, the mapping uncovers an existence of curious regimes where non-uniform deformations allow to achieve unique localization of band edges in momentum space that cannot be realized under either uniform or uniaxial deformations. For all other systems, the strain mapping is shown to provide deeper insight into the known trends of band gap modulation and direct-indirect transitions under strain. Hence, we prove that the standard way of analyzing selected strain directions is insufficient for some 2d systems, and a more general mapping strategy should be employed instead.