Theoretical study of the structural, cohesive, electronic and thermodynamic properties of Cu-Sb intermetallic compounds

A.F. GARCÍA ECHEVERRÍA; C. DELUQUE TORO; A.S. MOSQUERA POLO; S.B. RAMOS; A. FERNÁNDEZ GUILLERMET

San Carlos de Bariloche

Simposio; XXIII Latin American Symposium on Solid State Physics (SLAFES XXIII); 2018

Centro Atómico Bariloche (CNEA)

The current search for alloys appropriate for lead-free solderingapplications has motivated a long-standing effort to establish the relevantproperties of the alloys formed by Cu, i.e., the usual contact material, withthe binary systems which are intended to replace the classical Sn-Pblow-melting alloy. The main part of the studies in the last decades focused onthe alloys formed by Cu with a key candidate for such a replacement, viz., the In-Snsystem. More recently, there has been a growing interest in the effect of adoptingother related binaries, in particular, the Sn-Sb system, upon the quality andreliability of the joints. Since these aspects depend upon the properties ofthe intermetallic compounds (ICs) formed by Cu with Sn and Sb, it is necessaryto characterize in detail the physical properties of these ICs. In thiscontext, the present study focuses on the properties of the ICs formed by Cuwith Sb. Specifically, this work deals with the following ICs, which occur inthe Cu-Sb phase diagram: Cu2Sb-tP6,Cu3Sb-cF16, Cu3Sb-oP8, Cu10Sb3-hP26,Cu11Sb3-oC28. The structural, thermodynamic andelectronic properties of these ICs are established theoretically in theframework of the Density-Functional Theory (DFT), using the Projector AugmentedWaves (PAW) method in the Generalized Gradient (GGA) and Local-Density (LDA)approximation. Once the ground-state properties were established, variousquantities describing the thermal and equation-of-state behavior at finitetemperatures were determined, viz., CP, CV, and the Debyetemperature, the thermal expansion coefficient and the Grüneisen parameter.Trends in the variation of these properties are established, and a comparisonwith the behavior of the related Cu-In and Cu-Sn alloys, recently studied bythe current authors is reported