Memristors with nonvolatile memory characteristics have been expected to open a new era for neuromorphic computing and digital logic. However, existing memristor devices based on oxygen vacancy or metal‐ion conductive filament mechanisms generally have large operating currents, which are difficult to meet low‐power consumption requirements. Therefore, it is very necessary to develop new materials to realize memristor devices that are different from the mechanisms of oxygen vacancy or metal‐ion conductive filaments to realize low‐power operation. Herein, high‐performance and low‐power consumption memristors based on 2D WS2 with 2H phase are demonstrated, which show fast ON (OFF) switching times of 13 ns (14 ns), low program current of 1 µA in the ON state, and SET (RESET) energy reaching the level of femtojoules. Moreover, the memristor can mimic basic biological synaptic functions. Importantly, it is proposed that the generation of sulfur and tungsten vacancies and electron hopping between vacancies are dominantly responsible for the resistance switching performance. Density functional theory calculations show that the defect states formed by sulfur and tungsten vacancies are at deep levels, which prevent charge leakage and facilitate the realization of low‐power consumption for neuromorphic computing application.

Utilizing the instability of the edge atoms of graphene defects, carbon conductive filaments were formed under the regulation of the electric field and the synaptic function was achieved.

A model based on carbon conductive filaments (CFs) for a memristor based on carbon quantum dots (QDs) is proposed for the first time.

We report on the study of both perpendicular magnetic anisotropy (PMA) and Dzyaloshinskii-Moriya interaction (DMI) at the oxide/ferromagnetic metal (FM) interface, i.e. BaTiO3 (BTO)/CoFeB. Thanks to the functional properties of the BTO film and the capability to precisely control its growth, we are able to distinguish the dominant role of the oxide termination (TiO2 vs BaO), from the moderate effect of ferroelectric polarization in the BTO film, on the PMA and DMI at the oxide/FM interface. We find that the interfacial magnetic anisotropy energy of the BaO-BTO/CoFeB structure is two times larger than that of the TiO2-BTO/CoFeB, while the DMI of the TiO2-BTO/CoFeB interface is larger. We explain the observed phenomena by first principles calculations, which ascribe them to the different electronic states around the Fermi level at the oxide/ferromagnetic metal interfaces and the different spin-flip process. This study paves the way for further investigation of the PMA and DMI at various oxide/FM structures and thus their applications in the promising field of energy-efficient devices.

Electric-field control of magnetocrystalline anisotropy energy (MAE) is important for the optimal performance of the tunnel junction components of the STT-MRAM. In such a device, a high MAE of the free magnetic layer improves storage robustness, whereas a low MAE is also useful to keep energy expenditure in the switching process at a minimum. Using the frozen potential method to calculate the MAE of the CoFe layer, the electric-field control of MAE in the BaTiO3/CoFe/(Hf, Ta, W, Re, Os, Ir, Pt, or Au) heterostructure is studied. Electric field tuning of MAE is determined to be possible through switching the direction of BaTiO3 ferroelectric polarization, although both the tuning effect and the MAE depend strongly on the choice of the 5d transition metal element in the capping layer. The results predict a complicated behavior of both MAE and the underlayer polarization effect as we progress down the 5d series of elements as the choice of the capping layer element. Using the second-order perturbation theoretical framework, this behavior can nevertheless be explained by mechanisms including CoFe/capping layer interface hybridization and 5d band-filling trends in the capping layer.