Electronic and Optical Properties of 2D Antimonene and Bismuthene Phases from Many-Body Ab initio Approaches

New two-dimensional (2D) materials with band gaps compatible with broadband optoelectronic device applications, LEDs and photovoltaics are needed. 2D forms of the Antimony and Bismuth of Group VA, namely Antimonene and Bismuthene have intriguing electronic properties, being indirect semiconductors. [1,2] The band gaps near visible and ultra-violet (UV) regions are indicative of their promising optoelectronic properties aimed for UV or blue light. Single-layer (SL) honeycomb buckled and washboard structures of Sb and Bi are theoretically confirmed to be stable. An extensive investigation of their structural, electronic and optical properties were performed, using density functional and many-body perturbation theories combined with Random Phase Approximation (RPA) and Bethe-Salpeter equation (BSE). While spin-orbit coupling effects coupled with HSE show an increasingly dramatic effect on the optoelectronic properties of group-VA depending on their atomic numbers, bound excitons stand proof of the many-body effects being crucial for altering the optical properties of group-VA phases.

[1] O. U. Akturk et.al., PRB 91, 235446 (2015).
[2] E. Akturk et.al., PRB 94, 014115 (2016).
[3] D. Kecik et.al., to be published (2017).