Theoretical search for possible Au-Si crystal structures using a genetic algorithm

Abstract

Abstract:We performed a global search for possible Au-Si crystal structures using genetic algorithm (GA) combined with density functional theory (DFT) calculations. Two Au-Si structures of Au 8 Si 8 and Au 16 Si 8 were found to be energetically stable and have no imaginary frequencies by phonon calculations. The formation energies of all the studied structures gave a convex hull of Au-Si system, showing that the most stable composition was Au-Si = 1:1, and the Si-rich structures were much less stable than the Au-rich ones.

Novel superconducting structures of BH2 under high pressure

“…The unbiased global structural search based on GA method combined with first-principles structural relaxation is very effective to search a large structural phase space, which has been extensively applied to the structural prediction of crystals and clusters. [39][40][41] In this work, the GA search to obtain low-enthalpy structures was proceeded as follows: (i) structural search started from 40 initial random structures and these structures are relaxed by DFT calculations; (ii) using the cut-and-pasted operation, 10 offspring structures were generated based on the 40 parent structures at each GA generation; (iii) after the 10 offspring structures were fully relaxed by DFT calculations, 40 low-enthalpy structures are selected from the total 50 structures to evolve into next generation of GA. Candidate structures obtained from the GA search were further refined using the DFT calculations.…”

Theoretical Study on Fe–Se–H Hydrides under High Pressure

“…We searched for the stable structures of the Fe–Se–H compounds at the pressure range of 150–300 GPa by means of genetic algorithm (GA) method combined with first-principles structural optimization using density functional theory (DFT) with Perdew–Burke–Ernzerhof (PBE) functional implemented in the CASTEP code of Materials Studio package. − In structural optimization, the energy cutoff for the truncation of plane wave basis was taken to be 800 eV and a Brillouin zone k -point sampling with a resolution of 2π × 0.03 Å –1 was used. Genetic algorithm (GA) is a global structure search method which has been successfully applied to structure search for many systems, e.g., C 60 , atomic structure of Zr 2 Co 11 , layered structure of Cu 2 Te and Cu 2 Se, and bulk structure of Au–Si, etc. In the structural searching, the number of structures in each generation was set to 60.…”

Structures and Superconducting Properties of Ultra‐Hydrogen‐Rich Selenium Hydride H6Se

“…We performed the crystal structural search for H 6 Se by using the unbiased genetic algorithm (GA) method combined with density functional theory (DFT) calculations for structural optimization . The GA scheme is the same as that used in previous studies of clusters and crystal structures . In the GA search of the H 6 Se low‐enthalpy structures at 100, 200, and 300 GPa, the unit cells were designed to contain 1–4 formula units (f.u.).…”