Prediction of two-dimensional BiSb with puckered structure

Using global particle-swarm optimization method and first-principles calculations, we predict that the monolayer BiSb with puckered structure (p-BiSb) enjoys lowest energy in the configurations of the single layer BiSb theoretically predicted until now. Its moderate direct band gap predicted with HSE functional indicates that it is promising for further nano-electronic and nano-optical devices. Our calculations also reveal that uniaxial strain is an effective way to modulate its band gap. More importantly, p-BiSb shows relatively large piezoelectric coefficient, indicating its potential for sensors. Top and side view of the structure of p-BiSb and relaxed-ion polarization change under applied uniaxial strain (epsilon 11) along the a direction of p-BiSb. (C) 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.