The density functional theory (DFT) was used to investigate the mechanical properties of the pristine, hydrogenated, and fluorinated germanene sheets, including Young's and bulk moduli, and plastic properties. Young's and bulk moduli were calculated through the second derivation of the total energy versus strain. The electronic properties, namely the planar electron difference density and partial DOS were considered to evaluate the bonding characteristics of the structures. The results show that the adsorption decreases the electron accumulation between Ge atoms, which leads to weaker covalent bonds and reduced Young's and bulk moduli. Furthermore, it is observed that the yield strain of fully fluorinated germanene remains unchanged under uniaxial loading in comparison with the pristine structure. However, the yield strain of the hydrogenated germanene is increased under biaxial loadings. Our results show that germanene has a good mechanical tenability using surface functionalization.

密度泛函理论（DFT）用于研究原始的，氢化的和氟化的锗烯片材的机械性能，包括杨氏模量和体积模量以及塑性性能。杨氏模量和体积模量是通过总能量对应变的二次推导来计算的。考虑电子特性，即平面电子差密度和部分DOS，以评估结构的键合特性。结果表明，吸附减少了Ge原子之间的电子积累，从而导致较弱的共价键和降低的杨氏模量和体积模量。此外，观察到与原始结构相比，在单轴载荷下，完全氟化的锗烯的屈服应变保持不变。然而，在双轴载荷下，氢化锗烯的屈服应变增加。我们的结果表明，使用表面官能化，锗烯具有良好的机械强度。