Revisiting the energy barrier of black phosphorous and monochalcogenide monolayers*

The energy barrier is the energy required to change the rectangular unit cell of black phosphorene or monochalcogenide monolayers onto a square unit cell. Here, three different DFT codes were employed to obtain these barriers. It is known that the energy barrier decreases with the increase of the average atomic number [1], but in calculations performed with van der Waals corrections, the barrier is higher than our previously reported values. Also, we found that the ionicity, which is related to the average atomic number [2], has a linear relation with the energy barrier.

References
1 M. Mehboudi, A. M. Dorio, W. Zhu, A. van der Zande, H. O. H. Churchill, A. A. Pacheco-Sanjuan, E. O. Harriss, P. Kumar, and S. Barraza-Lopez, Nano Lett. 16, 1704 (2016).

2 P B Littlewood, J. Phys. C: Solid State Phys. 13, 4855 (1980).