The Space Group of Nd3Fe29-xTix: A2/m or P21/c

Abstract

PACS: 61.50.Ah; 61.50.LtThe structures of Nd-Fe compounds in 1 : 5, 1 : 12 and 2 : 17 are studied by the inverted ab initio potentials. The calculated lattice parameters are corresponding well to the experimental results. The site preference of Ti atoms in R 3 Fe 29Àx M x is evaluated and the space group of Nd 3 Fe 29Àx Ti x is identified as A2/m in the lower tolerance range. Moreover, the cohesive energy difference between A2/m and P2 1 /c is investigated, indicating that Nd 3 Fe 29Àx Ti x belongs to A2/m. So a divergence of opinion on the space group of R 3 Fe 29Àx M x -type structures is resolved successfully by the inverted ab initio potentials.

An inverse adhesion problem for extracting interfacial pair potentials for the Al(0 0 1)/3C–SiC(0 0 1) interface

“…It demonstrates that both the Al-Si and Al-C interactions are attractive, while the latter is much stronger than the former. For convenience, these two potentials are fitted into a modified Rahman-Stillinger-Lemberg functional form (16), with the parameters listed in table 1, It is worth paying attention to the validity and transferability of these potentials. First, for a self-consistent check we recalculate the adhesive energies E Si-term and E C-term in (3) by the inversed potentials shown in figure 2(a).…”

“…A main assumption of this method is that the adhesive energy is equal to the sum of pair interactions across the interface, which is a primary but practical approximation for the metal/semiconductor interface. Previously, by using the Chen-Möbius inversion method, we have studied a series of material systems, including the ionic crystals [14], semiconductors [15], metal-rare earth compounds [16] and metal/oxide interfaces [17], etc. Stimulated by these successes, we go deeper into the atomistic description of metal/semiconductor interfaces now.…”

Pair potential approach for metal/Al2O3interface

“…In this work, we obtain a concise inversion formula for a Ni/Al 2 O 3 interface, and then use it to extract the free-standing interfacial potentials from ab initio adhesive energies. This is a part of the systematic work in the frame of the Chen-Möbius inversion method, which began in the 1990s with Chen [11] and has gone through ionic crystals [12], rare earth compounds [13], semiconductors [14] and metal/MgO interfaces [15,16].…”

Atomistic simulation for the structural properties of Th–T and Th–T–In compounds (T = Fe, Co, Ni, Cu)

“…This may explain that most ThT 5 and Th 2 T 17 compounds have been synthesized, whereas no report on Th 3 T 29 and ThT 12 compounds was found. Note that all the above results are very similar to our previous works on rare earth intermetallics [8,9]. It is unexpected that we get so successful results by only pair potentials.…”