Interatomic pair potentials from DFT and molecular dynamics for Ca, Ba, and Sr hexaborides

Abstract

Alkaline earth hexaborides are thermoelectric materials with unique thermophysical properties that have a broad variety of applications with great potential for new uses in fields such as light-weight armor development, gas storage, and n-type thermoelectrics. In this work, we introduce a modeling framework to simulate the basic mechanical behavior of these materials with molecular dynamics. We use a combination of density functional theory, molecular dynamics, and optimization methods to produce a set of interatomic potentials which can describe accurately the equilibrium energetics and mean-square displacements of atoms within these bulk hexaborides. The model works particularly well for hexaborides with large cations.

Metal Hexaboride Work Functions: Surface Configurations and the Electrical Double Layer from First‐Principles

“…5 In addition to the stability of these materials, many electronic properties can be affected by the particular choice of metal. [6][7][8][9] Resulting properties can generally be inferred from the valence and polarization of the host cation along with the required electron donation-hexaborides having di-valent metals tend to produce semiconductors, while inclusion of a tri-valent metal allows for metallic conductivity. Electronic properties near the surface are also affected by the type of metal; however, additional degrees of freedom such as the atomic configuration will also affect observed properties, e.g., catalysis, adsorption, and emission.…”

Morphology Control of Tantalum Carbide Nanoparticles through Dopant Additions

“…Strain effects have also been explored as parameters for morphological modification of copper and nickel particles, and doping has been applied for obtaining nanorods of magnesium . In addition, modeling − and experimental techniques − have been applied for exploring the behavior of borides of cubic and other morphologies. Moreover, experimental efforts have investigated shape change in cubic carbides as a function of carbon stoichiometry, which influences the relative growth rate of the dominant {111} and {100} facets. − …”

Interaction of Hydrogen with MB6 (M = Ba, Ca, La, and Sr) Surfaces from First Principles

“…Experimental and theoretical studies investigating adsorption on MB 6 surfaces have mainly focused on determining the poisoning effects on the emitter planes caused by common environmental gases such as CO, O 2 , and H 2 O. − Although hydrogen is considered a background gas in ultrahigh vacuum conditions, only a handful of studies consider the interaction of hydrogen with MB 6 surfaces and theoretical investigations are absent from the literature to the best of our knowledge. Most experimental, modeling, and theoretical efforts are focused on electronic behavior and thermophysical properties for bulk MB 6 materials. − …”