Ferroelectric-Induced Phase Change Device with Polymorphic Mo_1-xW_xTe₂ for Neuromorphic Computing

While phase change devices have emerged as promising candidates for implementing artificial synapses, conventional phase change materials have faced challenges such as high-power consumption and limited reliability, originating from their Joule heating-driven phase transition mechanisms. Here, a phase change device based on a 2D material, Mo_0.95W_0.05Te₂ is demonstrated, which exhibits a phase transition between semiconducting 2H and semimetallic 1T' structural phases, facilitated by a ferroelectric substrate. The structural phase transitions are confirmed by Raman spectroscopy under drain or gate voltage bias. These bias conditions allow two types of operation to be realized in a single device structure, resulting in gate voltage modulation and drain voltage modulation with a ferroelectric substrate. The ferroelectric-induced phase change device exhibits key synaptic functions, including short-term and long-term plasticity, along with highly linear and symmetric multilevel conductance states. Furthermore, polymorphic Mo_0.95W_0.05Te₂ enables energy consumption as low as 5.3 pJ per switching event at monolayer thickness beyond conventional 3D phase change memory. These features highlight the potential of 2D material-based phase change devices on ferroelectric substrates as energy-efficient and high-performance components for next-generation neuromorphic computing systems.