Electronic, Excitonic, and Optical Properties of Zinc Blende Boron Arsenide Tuned by Hydrostatic Pressure.

Based on first-principles calculations combined with a maximally localized Wannier function tight-binding method and the Bethe-Salpeter equation formalism, we theoretically investigate the effects of hydrostatic pressure on the electronic, excitonic, and optical properties of zinc blende boron arsenide. Our findings show: (i) a pressure-induced semiconductor-to-metallic phase transition without causing any change in the structural crystallographic ordering, (ii) a decrease in excitonic binding energy with increasing pressure as a consequence of band gap engineering, and (iii) a small excitonic response in the indirect absorption regime due to the indirect band gap.

Stability and Optoelectronic Properties of Two-Dimensional Gallium Phosphide.

Using first-principles calculations, density functional theory, and the tight-binding method, we investigate the optoelectronic properties of two-dimensional gallium phosphide (2D GaP). Our investigation covers electronic properties, such as band structure and electronic band gap, and optical properties, including absorption spectra, refractive index, and reflectivity, considering excitonic effects. Additionally, structural aspects such as stability, elastic properties, and Raman and infrared spectra are also analyzed.

Visualization and Manipulation of Bilayer Graphene Quantum Dots with Broken Rotational Symmetry and Nontrivial Topology.

Electrostatically defined quantum dots (QDs) in Bernal stacked bilayer graphene (BLG) are a promising quantum information platform because of their long spin decoherence times, high sample quality, and tunability. Importantly, the shape of QD states determines the electron energy spectrum, the interactions between electrons, and the coupling of electrons to their environment, all of which are relevant for quantum information processing. Despite its importance, the shape of BLG QD states remains experimentally unexamined.