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

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.