Thermo-mechanical response of pristine and defective 2D hexagonal boron oxide

Understanding the fundamental properties in two-dimensional group-III chalcogenides materials and the development of methods to characterize and control their collective behavior is a topical area that attracts enormous interest. In this work, using molecular dynamics simulations, we report on the effect of temperature, crack length and point defects on the tensile properties of the BO monolayer. BO monolayer is found to be more flexible to deform but it is harder to break compared to other two-dimensional hexagonal materials. It is also demonstrated that the tensile properties are very sensitive to temperature along the armchair and zigzag directions. Furthermore, cracks at different lengths considerably impact the fracture behavior of the BO nanosheet, whereas crack elongation has no influence on Young's modulus. For nano-cracks, the limitation of the relevancy of Griffith's criterion for the BO sheet, with respect to MD simulations, is highlighted. Mono- and bi-vacancy defects, patterned perpendicular to the loading direction, greatly influence the reduction of the fracture strength. This study illustrates BO monolayer as a potential material for use in stretchable applications and in future thermo-mechanical devices.