Using first principle calculations based on density functional theory (DFT), we have investigated the mechanical properties of monolayer 8-Pmmn borophene, including ideal strength and critical strain. It was found that monolayer 8-Pmmn borophene can withstand stress up to 21.59 N m?1 and 27.79 N m?1 in a and b directions, respectively. The ultimate tensile strain along the a direction is about 0.155, and 0.16 along the b direction, which is larger than that of stripe borophene. Furthermore, the phonon dispersions under the three applied strains indicate that the mechanical failure in 8-Pmmn borophene is likely to originate from the elastic instability. Our study shows that 8-Pmmn borophene is a hard but flexible 2D material, and may potentially be useful in high-strain engineering applications.
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机译：使用基于密度泛函理论（DFT）的第一性原理计算，我们研究了单层8- Pmmn 硼苯的力学性能，包括理想强度和临界应变。发现单层8- Pmmn 硼苯可以承受的应力高达21.59 N m ？1 和27.79 N m 在 a 和 b 方向分别为？1 。沿 a 方向的极限拉伸应变约为0.155，沿 b 方向的极限拉伸应变约为0.16，这大于条状硼芬。此外，在三个施加应变下的声子色散表明，8- 硼苯的机械破坏可能源自弹性不稳定性。我们的研究表明8- Pmmn 硼苯是一种坚硬但具有弹性的2D材料，可能在高应变工程应用中很有用。
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