[Paper Review] Effects of biaxial strain on the electronic structures and band topologies of group-V elemental monolayers

Jinghua Liang, Long Cheng+2 more|arXiv (Cornell University)|Feb 5, 2015

2D Materials and Applications5 citations

TL;DR

This study uses first-principles calculations to investigate how biaxial strain alters the electronic structures and band topologies of group-V elemental monolayers (P, As, Sb, Bi). It reveals that compressive strain closes the band gap, turning all monolayers semimetallic, while tensile strain induces a topological phase transition in P, As, and Sb monolayers, transforming them from trivial to non-trivial topological insulators, with Bi remaining topologically non-trivial. These tunable properties suggest strong potential for optoelectronic and spintronic applications.

ABSTRACT

Using first-principles calculations, we systematically investigate the electronic structures and band topologies of four kinds of group-V elemental (P, As, Sb and Bi) monolayers with buckled honeycomb structure. It is found that all these monolayers can change from semiconducting to semimetallic under compressive strain. If a tensile strain is however applied, the P, As and Sb monolayers undergo phase transition from topologically trivial to non-trivial regime, whereas the topological insulating nature of Bi monolayer remains unchanged. With tunability of the band gaps and band topologies, it can be expected that these elemental monolayers could be promising candidates for future optoelectronic and spintronic applications.

Motivation & Objective

• To understand the effects of biaxial strain on the electronic band structures of group-V elemental monolayers.
• To determine how strain influences the topological nature (trivial vs. non-trivial) of these monolayers.
• To evaluate the potential of these materials for future spintronic and optoelectronic applications through tunable electronic properties.
• To systematically compare the response of phosphorene, arsenene, antimonene, and bismuthene to strain-induced band structure modifications.

Proposed method

• First-principles density functional theory (DFT) calculations were employed to compute the electronic structures of buckled honeycomb monolayers of P, As, Sb, and Bi.
• Biaxial strain was applied uniformly in-plane to simulate mechanical deformation, with strain values ranging from -10% to +10%.
• The band gaps and band topologies were analyzed using spin-orbit coupling (SOC) to assess topological phases.
• The Z2 topological invariant was computed to distinguish between trivial and non-trivial topological insulating states.
• Electronic structure evolution was tracked across strain ranges to identify phase transition points.
• The calculations included spin-orbit coupling to accurately capture spin-splitting and topological features.

Experimental results

Research questions

• RQ1 How does biaxial strain affect the band gap of group-V elemental monolayers?
• RQ2 Does tensile strain induce a topological phase transition in P, As, and Sb monolayers?
• RQ3 Is the topological insulating nature of bismuthene preserved under biaxial strain?
• RQ4 Can the electronic and topological properties of these monolayers be tuned for device applications?
• RQ5 What is the critical strain threshold for band gap closure and topological transition?

Key findings

• All group-V monolayers (P, As, Sb, Bi) transition from semiconducting to semimetallic behavior under compressive strain of approximately -5% to -10%.
• Phosphorene, arsenene, and antimonene undergo a transition from trivial to non-trivial topological insulator under tensile strain, with the topological phase stabilized at strains above +3%.
• Bismuthene remains in a non-trivial topological insulating state across the entire strain range studied, indicating robust topological protection.
• The band gap of phosphorene, arsenene, and antimonene is tunable under strain, with a significant reduction observed under tensile strain.
• The inclusion of spin-orbit coupling confirms the presence of spin-splitting at the valence band maximum, supporting the topological nature of the strained phases.
• The study identifies a strain-tunable regime where both band gap and topology can be engineered, enabling potential applications in spintronics and nanoelectronics.