Andriy O. Lyakhov

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We have developed a method for prediction of the hardest crystal structures in a given chemical system. It is based on the evolutionary algorithm USPEX (Universal Structure Prediction: Evolutionary Xtallography) and electronegativity-based hardness model that we have augmented with bond-valence model and graph theory. These extensions enable correct(More)
Under pressure, metals exhibit increasingly shorter interatomic distances. Intuitively, this response is expected to be accompanied by an increase in the widths of the valence and conduction bands and hence a more pronounced free-electron-like behaviour. But at the densities that can now be achieved experimentally, compression can be so substantial that(More)
a r t i c l e i n f o a b s t r a c t Evolutionary crystal structure prediction proved to be a powerful approach in discovering new materials. Certain limitations are encountered for systems with a large number of degrees of freedom (" large systems ") and complex energy landscapes (" complex systems "). We explore the nature of these limitations and(More)
Once the crystal structure of a chemical substance is known, many properties can be predicted reliably and routinely. Therefore if researchers could predict the crystal structure of a material before it is synthesized, they could significantly accelerate the discovery of new materials. In addition, the ability to predict crystal structures at arbitrary(More)
We present new developments of the evolutionary algorithm USPEX for crystal structure prediction and its adaptation to cluster structure prediction. We show how to generate randomly symmetric structures, and how to introduce ‘smart’ variation operators, learning about preferable local environments. These and other developments substantially improve the(More)
From detailed assessments of electronic structure, we find that a combination of significantly quantal elements, six of seven atoms being hydrogen, becomes a stable metal at a pressure approximately 1/4 of that required to metalize pure hydrogen itself. The system, LiH(6) (and other LiH(n)), may well have extensions beyond the constituent lithium. These(More)
Qiang Zhu,1,* Artem R. Oganov,1,2 Miguel A. Salvadó,3 Pilar Pertierra,3 and Andriy O. Lyakhov1 1Department of Geosciences, Department of Physics and Astronomy, and New York Center for Computational Sciences, Stony Brook University, Stony Brook, New York 11794, USA 2Geology Department, Moscow State University, 119992, Moscow, Russia 3MALTA Consolider Team,(More)
The stable crystal structure of LiBeH(3) is predicted on the basis of ab initio total-energy calculations using density-functional theory and an extended database of candidate structures and using global optimizations based on an evolutionary algorithm. At the level of density-functional theory, a CaSiO(3)_1-type structure with space group P2(1)/c,(More)
Sodium chloride (NaCl), or rocksalt, is well characterized at ambient pressure. As a result of the large electronegativity difference between Na and Cl atoms, it has highly ionic chemical bonding (with 1:1 stoichiometry dictated by charge balance) and B1-type crystal structure. By combining theoretical predictions and diamond anvil cell experiments, we(More)