Enhanced piezoelectricity of single layer Si–V (V[dbnd]N, P and As) compounds induced by uniaxial strain

Abstract

Based on the first-principles calculations, we investigate the strain effect on the mechanical, dynamical, electronic and piezoelectric properties of single-layer Si–V (VN, P and As) compounds. Our results predict that the elastic regions for SiN, SiP and SiAs are below 18%, 18% and 19% along the armchair direction, corresponding to the ideal strengths of 12.7 GPa, 4.9 GPa and 3.8 GPa. In the elastic region, we further ascertain the structures do not distortion until the strain exceeding to 14%, 16% and 17% by performing the ab initio molecular dynamics simulations at room temperature. In the above strain ranges, the structures always keep semiconducting property. Due to the non-central symmetry, the Si–V compounds exhibit piezoelectricity along the armchair direction. As the strain increases, the piezoelectric coefficients e11 and d11 increase with parabolic character, of which the d11 increase to 13.49 p.m./V, 51.61 p.m./V and 77.91 p.m./V, implying the enhancement of electromechanical coupling ability. Our results provide a guidance for single-layer Si–V compounds applied in piezoelectric fields.