Atom's Dynamics and Crystal Structure: An Ordinal Pattern Method.

The ubiquitous nature of thermal fluctuations poses a limitation on the identification of crystal structures. However, the trajectory of an atom carries a fingerprint of its surroundings. This rationalizes the search for a method that can determine the local atomic configuration via the analysis of the movement of an individual atom.

Calculated vibration spectrum of calcium hexahydroxodizincate dihydrate (qatranaite).

On the basis of first-principles electronic structure calculations, crystallographic parameters have been refined for calcium hydroxozincate (Qatranaite mineral), and the vibration properties (frequencies and eigenvectors) calculated. A detailed analysis of vibration modes is done, in the context of comparison with infrared and Raman spectra previously available. Special attention is paid to a posteriori symmetry analysis of vibration modes, discussing the latters' attribution to four irreducible representations of the P2/c space group, and to identifying stretchings and bendings of particular chemical bonds, pronounced in different vibrations.

Effect of the Indentation Load on the Raman Spectra of the InP Crystal.

Nanoindentations and the Raman spectroscopy measurements were carried out on the (001) surface of undoped and S-doped InP crystal. The samples were indented with the maximum load ranging from 15 mN to 100 mN. The phase transition B3→B1 was not confirmed by spectroscopic experiments, indicating a plastic deformation mechanism governed by dislocations activity.

Interatomic Potential for InP.

Classical modeling of structural phenomena occurring in InP crystal, for example plastic deformation caused by contact force, requires an interatomic interaction potential that correctly describes not only the elastic properties of indium phosphide but also the pressure-induced reversible phase transition B3↔B1. In this article, a new parametrization of the analytical bond-order potential has been developed for InP. The potential reproduces fundamental physical properties (lattice parameters, cohesive energy, stiffness coefficients) of the B3 and B1 phases in good agreement with first-principles calculations.

Structure and Properties of Copper Pyrophosphate by First-Principle Calculations.

Investigated the structural, electronic, and magnetic properties of copper pyrophosphate dihydrate (CuPPD) by the first-principle calculations based on the density functional theory (DFT). Simulations were performed with the generalized gradient approximation (GGA) of the exchange-correlation functional () supplemented by an on-site Coulomb self-interaction (-Hubbard term). It was confirmed that the GGA method did not provide a satisfactory result in predicting the electronic energy band gap width () of the CuPPD crystals.