Allotropes of Phosphorus with Remarkable Stability and Intrinsic Piezoelectricity

Direct and quasi-direct band gap silicon allotropes with remarkable stability.

In our present work, five previously proposed sp(3) carbon crystals were suggested as silicon allotropes and their stabilities, electronic and optical properties were investigated using the first-principles method. We find that these allotropes with direct or quasi-direct band gaps in a range of 1.2-1.6 eV are very suitable for applications in thin-film solar cells. They display strong adsorpti...

Structural principles of polyhedral allotropes of phosphorus.

We derive the structural principles of polyhedral allotropes of phosphorus, introducing three distinct families of black phosphorus nanostructures. The predicted tetrahedral, octahedral, and icosahedral phosphorus cages can also be considered as phosphorus fullerenes. Phosphorus cages up to P(888) are systematically investigated by quantum chemical methods, and their thermodynamic stabilities a...

Van der Waals interactions in selected allotropes of phosphorus

Selected allotropes of phosphorus are investigated by different levels of density functional theory (DFT) calculations to evaluate the relative stability orders with a special focus on the role of van der Waals interactions. Phosphorus is an excellent reference system with a large number of allotropes. Starting from low-dimensional molecular (0D, white P) and polymer structures (1D, P nanorods)...

Piezoelectricity in Lead-Zirconate-Titanate Ceramics – Extrinsic and Intrinsic Contributions

a comparison of teachers and supervisors, with respect to teacher efficacy and reflection

supervisors play an undeniable role in training teachers, before starting their professional experience by preparing them, at the initial years of their teaching by checking their work within the proper framework, and later on during their teaching by assessing their progress. but surprisingly, exploring their attributes, professional demands, and qualifications has remained a neglected theme i...