Flexible MA2Z4 (M = Mo, W; A = Si, Ge and Z = N, P, As) monolayers with outstanding mechanical, dynamical, electronic, and piezoelectric properties and anomalous dynamic polarization

We systematically investigate the mechanical, dynamical, and piezoelectric properties of MA 2 Z 4 monolayers (M = Mo, W; A = Si, Ge and Z = N, P, As) based on first-principles calculations.