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• A vertically-integrated ferroelectric memristor demonstrated by the 2D ferroelectric ferroelectric heterojunction. • Memristive behaviour and bassic synaptic functions were realized. • Memristive behaviour and synaptic features can be effectively gate tuned by applying a gate potential. Memtransistor, a multi-terminal device that combines both the characteristics of a memristor and a transistor, has been intensively studied in two-dimensional layered materials (2DLM), which show potential for applications in such as neuromorphic computation. However, while often based on the migration of ions or atomic defects in the conduction channels, performances of memtransistors suffer from the poor reliability and tunability. Furthermore, those known 2DLM-based memtransistors are mostly constructed in a lateral manner, which hinders the further increasing of the transistor densities per area. Until now, fabricating non-atomic-diffusion based memtransistors with vertical structure remains challenging. Here, we demonstrate a vertically-integrated ferroelectric memristor by hetero-integrating the 2D ferroelectric materials CuInP 2 S 6 (CIPS) into a graphite/CuInP 2 S 6 /MoS 2 vertical heterostructure. Memristive behaviour and multi-level resistance states were realized. Essential synaptic behaviours including excitatory postsynaptic current, paired-pulse-facilitation, and spike-amplitude-dependent plasticity are successfully mimicked. Moreover, by applying a gate potential, the memristive behaviour and synaptic features can be effectively gate tuned. Our findings pave the way for the realization of novel gate-tunable ferroelectric synaptic devices with the capability to perform complex neural functions. [Display omitted] [ABSTRACT FROM AUTHOR]

Recent work has shown the significance of a nonlocal dielectric response and surface correction for nanometer-length-scale plasmonic structures. In this paper, we propose a new surface hydrodynamic model which incorporates such nonlocality and surface correction. Our approach, which is based on the hydrodynamic model, uses a numerical approach based on full-wave numerical computation and thus enables calculation of surface plasmon polariton (SPP) fields. The model also introduces a discontinuity in the normal component of the electric displacement at the interface by taking into account the change in the electron distribution at the interface. The method makes use of the Feibelman d parameter approach for the surface correction by equating the corrected Fresnel reflection of a p-polarized incident field across a planar interface. To demonstrate our method, we first examine numerical calculation of SPP propagation at a single interface structure; this work is then followed by a demonstration for a set of more complex thin-film structures. The latter demonstrates that our method is suitable for use in numerical modeling of complex nanophotonic structures.

• Effect of spatial average and delay on the predator-prey model is investigated. • Conditions for stability, steady state bifurcation and Hopf bifurcation are obtained. • Algorithm of normal form of steady state-Hopf bifurcation for system with spatial average and delay is derived. • Spatiotemporal dynamical classification near the steady state-Hopf bifurcation point is studied. In this paper, we discuss a diffusive predator-prey model with nonlocality and delay. Stability and bifurcation analysis suggest that the joint impacts of the nonlocal term and delay result in instability of the positive constant steady state. Moreover, steady state, Hopf and steady state-Hopf bifurcations and interactions of these bifurcations may occur under certain conditions. Normal forms of steady state, Hopf and steady state-Hopf bifurcations for a general reaction-diffusion model with nonlocal effects and delay are derived. In numerical simulations, spatially inhomogeneous steady states and periodic solutions and heteroclinic connections between these solutions are obtained. [ABSTRACT FROM AUTHOR]