Ab initio investigation of layered TMGeTe3 alloys for phase-change applications

Abstract

Chalcogenide phase-change materials (PCMs) are among the most mature candidates for next-generation memory technology. Recently, CrGeTe₃ (CrGT) emerged as a promising PCM due to its enhanced amorphous stability and fast crystallization for embedded memory applications. The amorphous stability of CrGT was attributed to the complex layered structure of the crystalline motifs needed to initiate crystallization. A subsequent computational screening work identified several similar compounds with good thermal stability, such as InGeTe₃, CrSiTe₃ and BiSiTe₃. Here, we explored the substitution of Cr in CrGT with other 3d metals and predicted four additional layered alloys to be dynamically stable, namely ScGeTe₃, TiGeTe₃, ZnGeTe₃ and MnGeTe₃. Thorough ab initio simulations performed on both crystalline and amorphous models of these materials indicate the former three alloys to be potential PCMs with sizable resistance contrast. Furthermore, we found that crystalline MnGeTe₃ exhibits ferromagnetic behavior, whereas the amorphous state probably forms a spin glass phase. This makes MnGeTe₃ a promising candidate for magnetic phase-change applications.