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 Ga_0.8In_0.2 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 (r_Ga−In), the peak height of g(r), the total system energy (E_tot), and the system size (L). At T = 300 K, the alloy exhibited a predominantly face-centered cubic (FCC) local structure with r_Ga−In = 3.15 Å, g(r) = 5.56, L = 4.95 nm and E_tot = -16,032 eV. Upon cooling to 169 K and 90 K, the system undergoes a more ordered structural rearrangement, reflected in a decrease of E_tot 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 E_tot = –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 E_tot to –16,202 eV and a sharp increase in g(r) to 7.87, indicating enhanced local atomic ordering. Nevertheless, the decrease in E_tot 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.