Phase-Change Heterostructures Based on Antimony

Phase-change materials (PCMs) are employed in optical and electronic storage devices and are interesting candidates for neuromorphic computing. However, they exhibit some drawbacks that limit their application in this field, including a temporal drift in resistance and a stochastic variability of the conductance. To eliminate these problems, it has been proposed to use phase-change heterostructures made of alternating thin layers of PCMs and proper confinement materials, such as transition metal dichalcogenides. Herein, superlattice heterostructures consisting of TiTe2 and antimony are investigated by ab initio methods and neural-network interatomic potentials. The structural and kinetic properties of the relevant phases are characterized. A complete switching cycle is simulated and it is shown that very high quenching rates must be used to generate stable amorphous Sb layers. It is also shown that it is possible to switch the Sb layer without destroying the crystalline structure of TiTe2, which makes these superlattices potential candidates for neuro-inspired applications that do not require long retention times, such as computing-in-memory tasks.