Advanced Materials has published an article written by Shan He, Mengfan Guo, Yue Wang, Yuhan Liang, and Yang Shen, School of Materials Science and Engineering, State Key Lab of New Ceramics and Fine Processing, Tsinghua University, Beijing, 100084 China.
Abstract: “Multiplexing physical dimensions to realize multidimensional storage in single material has been a goal to increase storage density and data security. Multidimensional storage has been only achieved in optical storage material (OSM) by far. Poly(vinylidene fluoride) (PVDF), a semi-crystalline polymer, has been widely studied as an candidate for ferroelectric random access (FeRAM). Herein, we employed atomic force microscopy-based infrared spectroscopy (AFM-IR) technique to induce multi-level phase transformation in PVDF ultrathin film on nanometric scales and used it for writing/readout of IR signals. We demonstrate an optical/ferroelectric multiplexing PVDF memory, where information could be coded with independent four-level optical IR and bi-level ferroelectric signals. High data security and a storage density up to 180 GBit/inch2 are achieved simultaneously. Owing to the different critical temperature for phase transformation (optical data, <167 °C) and polarization switching (ferroelectric data, <100 °C), the multiplexing memory can function both as optical read-only memory (ROM) and FeRAM. This work expands material supporting physical dimensions multiplexing beyond OSM for the first time, opening up new opportunities for future high-capacity, multifunctional nano-memory. The strategy proposed here enables on-demand and tunable programming on IR waves, offering prospect for fabrication of active nano-optical devices.“