Effect of Cryogenic Temperature on the Stability and Structural Formation of Ga0.8In0.2 Semiconductor Alloy Using Molecular Dynamics Simulations

Abstract

The article investigates the cooling process of the Ga0.8In0.2 semiconductor alloy over the cryogenic temperature range (T) from 300 K to T = 4 K using molecular dynamics (MD) simulations. The structural characteristics are analyzed through the radial distribution function (RDF), including the Ga–In bond length (rGa−In), the peak height of g(r), the total system energy (Etot), and the system size (L). At T = 300 K, the alloy exhibited a predominantly face-centered cubic (FCC) local structure with rGa−In = 3.15 Å, g(r) = 5.56, L = 4.95 nm and Etot = -16,032 eV. Upon cooling to 169 K and 90 K, the system undergoes a more ordered structural rearrangement, reflected in a decrease of Etot from –16,032 eV to –16,142 eV, an increase of g(r) to 6.22, and a slight reduction in L. At T = 77 K, the alloy reaches Etot = –16,154 eV with g(r) = 6.56, corresponding to a continued decrease in total energy during the ordering process. Finally, at T = 4 K, the system approaches an almost frozen state, with a pronounced drop in Etot to –16,202 eV and a sharp increase in g(r) to 7.87, indicating enhanced local atomic ordering. Nevertheless, the decrease in Etot is insufficient to drive full crystallization, which provides quantitative insight into temperature-driven structural ordering within the predominantly FCC phase at cryogenic temperatures. These results provide a theoretical basis for experimental investigations of Ga–In semiconductor alloys in the low-temperature regime and offer valuable guidance for potential applications in electronic and semiconductor devices.