Liquid Of Ge <sub> 15 </ Sub> Te <sub> 85 </ Sub> First Principle Of The Abnormal Nature Of The Study

One of the most difficult problems in condensed matter physics is to describe the microscopic liquid state. Owing to the dynamical nature of the liquid state, it is not possible to discuss a given microscopic structure, only ensemble averages can be specified. Such averages can be performed via well crafted molecular dynamics simulations: the length of the simulation, the size of the ensemble and the nature of the interatomic forces must all be carefully analyzed.First principle calculations, which are based on density functional theory(DFT), can predict the properties if only the composition of the matter were known. Vienna Ab — initio Simulation Package(VASP), with projected augmented wave method implemented, can perform ab — inition calculations and have successed in liquids, as well as solid state matters.DFT was widely accepted by millions of chemists and physical scientists also. PAW, introduced by Bl(o|¨)ch in 1994, was all-electron method, in which charge density was decomposed further and wave functions were made up of plane waves, pseudo-wave functions, orbits of atoms and pseudo-atoms. Bonding structures and tail of the wave functions, as well as the nodes of the wave functions near the core, can be well described by PAW method simultaneity.In this paper, we illustrate this approach for eutectic alloy Ge₁₅Te₈₅. The density functional theory(DFT) bases calculations were performed in the generalized gradient approximation. The simulation results, such as microstructure, dynamical properties were presented. We found that the abnormality in thermal dynamical properties around the eutectic temperature came from the change of local environment of germanium, not of tellurium. Ge-Te bonding increases with the temperature rising from 673K to 733K, which makes the system more compact.