Theoretical investigations of misfit dislocations in Pd/MgO(001) interfaces

Abstract

This paper investigates the properties of dislocations in Pd/MgO(001) interfaces. By constructing ideal and virtual interface structures and applying the Chen–Mobius inversion method, we obtain interatomic potentials ΦPd–Mg and ΦPd–O directly from ab initio adhesive energies. Then, by applying the above potentials, as well as using the atomistic relaxation and molecular dynamics methods, stable interface structures are obtained. For simplicity, we use a two-dimensional model to provide some clear physical pictures of the dislocations. There are two kinds of mechanisms of dislocation formation: one is insertion of an extra slice of Pd atoms; the other is increasing the number of Pd layers, to produce dislocations via the increasing misfit stress. Finally, three-dimensional models are investigated, with dislocations perpendicularly intersecting in the interface. The calculated interfacial distances are in agreement with experiments.

Combining 2d-Periodic Quantum Chemistry with Molecular Force Fields: A Novel QM/MM Procedure for the Treatment of Solid-State Surfaces and Interfaces

“…In the case of ionic systems such as metal oxides the inclusion of the effective partial charges of the MM atoms close to the QM/MM boundary provides an adequate representation of the surrounding electrostatic potential. For example in the case of MgO values of ±2.0 e ( e corresponding to the elementary charge) for Mg and O appear adequate, although in some force field formulations the effective partial charges are chosen to be lower than the formal oxidation state (e.g., ±1.14 e for Zn and O in a novel potential model for ZnO). All partial charges q of the M embedding atoms are included as an additional potential into the electronic Hamiltonian Ĥ el of the n -electron QM system with N and Z being the number of nuclei and their associated charges, r representing a given distance vector, and the square of the del operator ∇ corresponding to the Laplacian.…”

“…In this work new parameters for the non-Coulombic QM-MM Lennard-Jones interaction have been derived based on the potential energy scan depicted in Figure 3a (see Supporting Information Figure S1). To describe the non-Coulombic interaction between MM particles the parameters reported by Long et al 86 have been employed.…”

Nanostructure, Plastic Deformation, and Influence of Strain Rate Concerning Ni/Al2O3 Interface System Using a Molecular Dynamic Study (LAMMPS)

“…After interface relaxation, the Ni slab and Al 2 O 3 slab were displaced along tensile direction or shear direction. For tensile test, the adhesive energy per unit area at different interface displacement is defined as [ 54 ] where is the total energy of the interface system at interface normal displacement relative to equilibrium interface distance. is the total energy of the isolated Ni(001) layer; is the total energy of the isolated -Al 2 O 3 (0001) layer; is the interface area.…”

Interfacial potential approach for Ag/ZnO (0001) interfaces

“…The Chen-Möbius method has been applied to many material systems such as ionic crystals, [22] semiconductors, [23] metalrare earth compounds, [24] metal/MgO interfacial system, [25] metal/SiC interfacial system, [26][27][28] random allays system, [29] and metal/GaN interfacial system. [30] As a further application of Chen-Möbius inversion, we now investigate the metal/ZnO interfacial system.…”