Thermodynamic Modeling of the Te-X (X = Gd, Dy, Ho) Binary Systems Combined with the First-Principles Method

Thermodynamic databases are essential to understanding alloy properties and guiding materials design. In this work, the mixing enthalpies of the liquid phase in the Gd-Te, Dy-Te and Ho-Te binary systems are calculated using Ab-initio Molecular Dynamics (AIMD) simulations and the thermodynamic parameters are determined using the CALculation of PHAse Diagrams (CALPHAD) method combined with the phase equilibrium data and thermodynamic data. The associated solution model is employed to describe the liquid phase of these systems. The sublattice model (Gd,Te)(0.0296)(Gd)(0.4)(Te)(0.5714), (Dy,Te)(0.0286)(Dy)(0.4286)(Te)(0.5714) and (Ho,Te)(0.5)(Te)(0.5) are utilized to describe Gd2Te3, Dy2Te3 and HoTe, respectively. The line compounds, i.e. GdTe, DyTe, and DyTe2, are modeled using the stoichiometric model. The calculated results can describe the experimental and thermodynamic information reported in the literature. In addition, the existence of a liquid-liquid separation in the Dy-rich side in the Dy-Te binary system is proposed in this work.