Strain-Dependent Band Structures and Electronic Properties in Sb/Bi Lateral Heterostructures Calculated by First Principles

2D material structures have drawn much attention because of the unique characteristics of carriers confined in 2D planes. Various structures have been fabricated for high-performance optoelectronic devices. Herein, via first principles, lateral heterostructures (LHSs) based on antimony (Sb) and bismuth (Bi) are predicted and band structures affected under strain are calculated. For Sb/Bi LHSs, zigzag and armchair atomic configurations are considered. By altering the number of atoms on two sides of the heterostructures, the Sb/Bi LHSs exhibit narrow bandgaps. Moreover, external compressive and tensile strains induce transitions from indirect to direct band structures and further compress the bandgap energy into the midinfrared range. Partial density-of-states analysis indicates that, under the applied strains, the valence band mainly comprises Bi 6p states and Sb 5p states. In addition, charge density distributions indicate that electrons are localized at Bi atoms, whereas holes are localized at Sb atoms, thus exhibiting spatial separation of carriers. A narrow-bandgap material in which the band structure and electronic structure characteristics have great potential for infrared optoelectronic applications is proposed herein.