Ultrahigh-strain ferroelasticity in two-dimensional honeycomb monolayers: from covalent to metallic bonding

• 来源期刊: 科学通报（英文版）
• 年，卷（期）: 2020,（2）
• 页码范围: 147-152
• 页数: 6页
• 语种: 英文

摘要

We propose a possible ferroelastic switching pathway of two-dimensional (2D) honeycomb lattice (including graphene,BN,stanene,etc.) that may swap its armchair and zigzag direction,reversing an unprecedented strain of 73.2％.Our ab initio calculations reveal that such pathway cannot work in covalent systems like graphene and BN;for monolayer with metallic bonds like stanene,stanane and InBi that have all been synthesized,however,such pathway can be feasible with a low switching barrier (＜0.15 eV) and stress (＜graphene upon 1％ tensile strain),also with the highest energy/stress point in the elastic region.Their distinct behaviors are attributed to the different feature of covalent bonds and metallic bonds:the former is rigid with directionality,while the latter is malleable with ductility.A general trend of linear decrease in switching barrier with uprising metallicity for the same group compounds is revealed.Similar behaviors can be extended to bulk zinc-blended or wurtzite structure that can be deemed as multilayer stacking of buckled monolayer.Binary compounds like InBi monolayer are even multiferroics with both in-plane and vertical ferroelectricity as well as nontrivial topological properties.