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Stress-sign-tunable Poisson's ratio in monolayer blue phosphorus oxide
Bowen Zeng1, Mengqiu Long1,2, Yulan Dong1
1Hunan Key laboratory of Super Micro-structure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha 410083, People's Republic of China.
Abstract:
Negative Poisson's ratio (NPR) materials have attracted tremendous interest due to their unusual physical properties and potential applications. Certain two-dimensional (2D) monolayer materials have also been found to exhibit NPR and the corresponding deformation mechanism varies. In this study, we found, based on first-principles calculations, that the Poisson's ratio (PR) sign of monolayer blue phosphorus oxide (BPO) can be tuned by strain: the PR is positive under uniaxial strain [Formula: see text] but becomes negative under [Formula: see text] > 0. The deformation mechanism for BPO under strain depends on the mutual competition between the P-P attraction and P-O repulsion effect, and these two factors induce two different deformation pathways (one with positive PR, and the other with NPR). Moreover, with increasing of strain, both the decreased strength of P-P attraction and the increased strength of P-O repulsion effect modulates the PR of BPO from positive to negative.