Communication: Van der Waals corrections for an improved structural description of telluride based materials

Abstract

Density functional theory (DFT), using the generalized gradient approximation, fails to reproduce the structure of liquid tellurides, which manifests by an overestimation of the interatomic bond distances. Here, we take into account dispersion forces in a semi-empirical way and apply such DFT simulations to liquid Ge15Te85. Substantial improvement of the simulated structure factor and pair distribution function is found, together with a change in the diffusion constant. A detailed analysis shows that such dispersion forces strongly affect the local geometry and first coordination shell of the atoms, whereas angular distributions remain unchanged.

Aging mechanisms in amorphous phase-change materials

“…In ref. 37, the semiempirical Grimme correction to DFT 38 was shown to reduce the deviations from experiments for Ge 15 Te 85 at high temperature. However, it fails to improve the agreement with experiments for amorphous GeTe (see Supplementary Note 1 and Supplementary Fig.…”

Quantitative measure of tetrahedral-sp3geometries in amorphous phase-change alloys

“…and a time step of t = 0.12 fs has been used to integrate the equations of motion. In addition, we used used an (attractive) empirical dispersion coefficient (Grimme) correction [27] that has been shown to substantially improve the structural properties of Ge-Te alloys, and increase the agreement with experimental data [28]. This (attractive) correction [27] is given by…”

Concepts and applications of rigidity in non-crystalline solids: a review on new developments and directions

“…The neat estimate of constraints from MD simulations [117,118] also permits to address an important issue in the field of phase change materials, i.e. the detection of Ge tetrahedral units and the measurement of their population with e.g.…”