Xiao Wen-Zhi, Xiao Gang, Wang Ling-Ling
School of Science, Hunan Institute of Engineering, Xiangtan 411104, China.
School of Physics and Electronics, Hunan University, Changsha 10082, China.
J Chem Phys. 2016 Nov 7;145(17):174702. doi: 10.1063/1.4966581.
We report the structural, electronic, magnetic, and elastic properties of a two-dimensional (2D) honeycomb stannic oxide (SnO) monolayer based on comprehensive first-principles calculations. The free-standing and well-ordered 2D centered honeycomb SnO (T-SnO) monolayer with D point-group symmetry has good dynamical stability, as well as thermal stability at 500 K. The T-SnO monolayer is a nonmagnetic wide-bandgap semiconductor with an indirect bandgap of 2.55/4.13 eV obtained by the generalized gradient approximation with the Perdew-Burke-Ernzerhof/Heyd-Scuseria-Ernzerhof hybrid functional, but it acquires a net magnetic moment upon creation of a Sn vacancy defect. The elastic constants obtained from the relaxed ion model show that the T-SnO monolayer is much softer than MoS. The bandgap monotonically decreases with increasing strain from -8% to 15%. An indirect-to-direct bandgap transition occurs upon applying biaxial strain below -8%. Synthesis of the T-SnO monolayer is proposed. We identify the Zr(0001) surface as being suitable to grow and stabilize the T-SnO monolayer. The unique structure and electronic properties mean that the T-SnO monolayer has promising applications in nanoelectronics. We hope that the present study on the stable free-standing SnO monolayer will inspire researchers to further explore its importance both experimentally and theoretically.
基于全面的第一性原理计算，我们报告了二维（2D）蜂窝状氧化锡（SnO）单层的结构、电子、磁性和弹性性质。具有D点群对称性的独立且有序的二维中心蜂窝状SnO（T-SnO）单层具有良好的动力学稳定性，以及在500 K时的热稳定性。T-SnO单层是一种非磁性宽带隙半导体，通过采用Perdew-Burke-Ernzerhof/Heyd-Scuseria-Ernzerhof混合泛函的广义梯度近似得到的间接带隙为2.55/4.13 eV，但在产生Sn空位缺陷时会获得净磁矩。从弛豫离子模型获得的弹性常数表明，T-SnO单层比MoS软得多。带隙随着应变从-8%增加到15%而单调减小。在施加低于-8%的双轴应变时会发生间接带隙到直接带隙的转变。提出了T-SnO单层的合成方法。我们确定Zr(0001)表面适合生长和稳定T-SnO单层。独特的结构和电子性质意味着T-SnO单层在纳米电子学中有广阔的应用前景。我们希望目前对稳定的独立SnO单层的研究将激励研究人员在实验和理论上进一步探索其重要性。
