Abstract
In this paper we discuss the use of the effective medium approach, an embedded atom method (EAM), to study the cohesion in, and structures of, intermetallic compounds. We show that the method includes important contributions to the cohesion of many such compounds, resulting from the proximity of different types of atoms, that are neglected in simple pair potentials. We also show that important contributions exist of the form calculated from pseudopotential pair potentials. We argue that these contributions are neglected in currently existing EAM schemes, but could be included in an improved effective medium model.
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References
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As we shall see, the computational method we use will only be reliable in this case.
The EAM is also discussed in several other papers in this symposium.
It would not be a good approximation for a system with many TM-TM nearest neighbors, since directional d-bonding will occur. However, in the Al-rich alloys under consideration, each TM atom is surrounded only by Al atoms, so the background electron gas will be fairly uniform.
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Of course, the numerical calculations using Eq. 1 properly take these competing effects into account. In particular, the V(r) used (the same as in ref. 6), while not oscillatory, does tend to push atoms to larger distances.
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© 1989 Plenum Press, New York
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Redfield, A.C., Zangwill, A. (1989). The Effective Medium Approach to the Energetics of Metallic Compounds. In: Vitek, V., Srolovitz, D.J. (eds) Atomistic Simulation of Materials. Springer, Boston, MA. https://doi.org/10.1007/978-1-4684-5703-2_16
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DOI: https://doi.org/10.1007/978-1-4684-5703-2_16
Publisher Name: Springer, Boston, MA
Print ISBN: 978-1-4684-5705-6
Online ISBN: 978-1-4684-5703-2
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