Gaokuo Zhong

The ferroics combine the single-hysteresis loop of ferroelectrics with the double-hysteresis loop of antiferroelectrics to form multiple hysteresis loops, which could substantially advance energy storage, electrocaloric cooling, and nonvolatile multistate memory technologies. However, the intentional stabilization of intermediate states that bridge the nonvolatility of ferroelectrics and the field-induced phase transition behavior of antiferroelectrics remains a fundamental challenge. Here, we propose a strategy for preparing lead zirconate (PbZrO ₃ ) thin film at low temperature, introducing a stable ferrielectric phase within the antiferroelectric to achieve triple-hysteresis loop under large electric fields. Microstructural features reveal that this behavior is attributable to the presence of Pb _Zr antisite defects acting as seeds for polar order, which induce the distinctive triple (↑↑↓) dipole modulation period configuration. To demonstrate the application potential, we evaluated the electrocaloric effect of triple-hysteresis PbZrO ₃ thin film based on Maxwell’s relations, the predicted temperature change Δ T can reach −23.76 kelvins, which is ~600% enhancement compared to double-hysteresis PbZrO ₃ antiferroelectric thin films. These findings establish a design paradigm for embedding stable ferroelectric switching within antiferroelectrics, which may unlock opportunities for developing high-density energy storage, nonvolatile multistate memory, and highly efficient switching devices.

Thin-film capacitors exhibit significant application potential owing to their rapid charge/discharge characteristics and high-power density. Individual engineering strategies can effectively enhance either breakdown strength (Ebre) or polarization difference to improve energy storage performance. However, such enhancement typically leads to unilateral optimization of either energy density (Wrec) or energy efficiency (η) and fails to achieve an optimal trade-off between these, resulting in limitation fundamentally constrains the simultaneous enhancement. In this work, we propose multi-level synergistic modulation strategy, realizing synchronous optimization of multiple parameters to achieve breakthrough in comprehensive energy storage performance. Taking classic BaTiO3 ferroelectric as example, we implemented interface engineering strategy to simultaneously enhance the Ebre and reduce remnant polarization. Combined with entropy optimization strategy, this approach further increased the Ebre while significantly boosting saturation polarization. The developed BaTiO3/SrTiO3-BiFeO3 superparaelectric film capacitor demonstrate exceptional energy storage performance, achieving ultrahigh η of 97.35% and high Wrec of 40.60 J/cm3, increasing to 133.56% and 492.72% comparing to the pure film. Moreover, the same system on flexible substrates shows comparable outstanding energy storage performance, with excellent operational stability across wide temperatures and under mechanical deformation. These results confirm the universality of strategy and pave the way for multifunctional flexible capacitors.

Functional oxide films offer precise control over diverse properties through tunable physical characteristics and interface effects, with their functionality primarily determined by morphology. However, conventional methods are incapable of obtaining large-scale morphological data and face significant challenges in data identification and classification, which fundamentally limit the rapid assessment of thin film properties and functional screening. Herein, we establish a comprehensive morphological database of oxide films utilizing high-throughput experimental methods and develop a machine learning framework for automated identification and classification of atomic force microscopy data. Using gradient-thickness SrRuO3 films as a representative example, this framework achieves enhanced performance through hyperparameter optimization and strategic adjustments, ultimately reaching a classification accuracy of 86.67% in independent tests, demonstrating its effectiveness in morphology analysis of functional oxide films. Furthermore, this approach shows significant potential for automated microstructure analysis of complex oxides and is expected to accelerate research on structure-property correlations in functional oxide films.

Biphenylene‐based structures with semiconducting characteristics hold great promise for nanoelectronics owing to their intrinsically anisotropic charge transport. Yet, achieving semiconducting behavior in these systems remains challenging due to their inherent metallic nature. Here, we propose a precise site‐specific N‐doping strategy that drives a secondary electronic transition in net W, enabling the electronic properties transition from metal to Dirac semimetal and ultimately to semiconductor. This transition is governed by the synergistic interplay of structural distortion, band‐filling, on‐site energy differences, and symmetry. The optimized THO‐C ₃ N‐2 and THO‐C ₃ N‐3 semiconductors exhibit high carrier mobilities (exceeding 10 ³ cm ² V ⁻¹ s ⁻¹ ) and pronounced mobility anisotropy, with THO‐C ₃ N‐2 achieving the highest electron mobility anisotropy ratio (2061.22) among reported 2D carbon nitride systems. This work not only establishes an effective band engineering paradigm for biphenylene‐based materials but also offers promising candidates for directionally tailored nanoelectronic devices.

Ferroelectric-based artificial synapses have emerged as fascinating candidates for the development of intelligent sensor–memory–computing (SMC) systems, thanks to the remarkable nonvolatile properties and abundant polarization states that ferroelectrics offer. However, simultaneously modulating the ferroelectric synapse through optical and electrical excitation is challenging. Herein, we propose a high-throughput strategy for designing optoelectronic co-modulated ferroelectric synapses. This strategy involves designing a ferroelectric field-effect transistor (FeFET) based on the Pb(Zr0.2Ti0.8)O3/InGaZnO (IGZO) heterostructure, which includes an IGZO homostructure, followed by high-throughput screening of IGZO materials that enable both optical and electrical modulation. The transistors with optoelectronic co-modulated synaptic functionalities are subsequently screened from a set of high-throughput FeFETs. Based on these optoelectronic co-modulated ferroelectric synapses, an artificial SMC system that can simultaneously sense and recognize images is constructed, achieving a high recognition accuracy of 88.42% and this SMC system simultaneously exhibits the advantages of reduced hardware overheads, fast speed and low power consumption. Our work introduces a novel strategy for designing multifunctional artificial synapses from materials to devices, which may represent a new paradigm in the development of high-performance SMC systems.

Ferroelectric negative capacitance is highly promising for reducing the power consumption of ferroelectric-based devices. However, the bistable nature limits the ferroelectrics that present one negative capacitance effect during ferroelectric switching. The direct experimental creation of multi-stage negative capacitance during ferroelectric switching remains elusive thus far. Here, we have observed the novel phenomenon of twice transient negative capacitance effects occurring at unidirectional operating voltages by constructing a ferroelectric superdomain in a (111)-PbZr0.2Ti0.8O3 film. This negative capacitance can be simply operated by a unidirectional voltage, differing from the conventional operation requirements that involve alternating positive/negative voltages or complex phase transitions. Moreover, we have observed four times negative capacitance during one cycle of voltage pulse scanning. The superdomain evolution under external electric fields reveals that the switching of the superdomain undergoes an intermediate state stage, and hence, a triple-well energy landscape associated with multi-stage negative capacitance is generated during polarization switching. The observation of the multi-stage negative capacitance effect in ferroelectric films offers prospects for the design of nanoelectronics based on negative capacitance.

The structure and properties of functional thin films are highly sensitive to their epitaxial orientations. However, the orientation of the thin film is typically constrained by that of the substrate, making it challenging to achieve distinct orientations between the thin film and the substrate. The use of buffer layers is an effective approach to manipulate the epitaxial orientations of functional thin films. Nevertheless, this method requires precise screening of buffer layer parameters that may influence the orientation of the overlying functional layer, making the process labor‐intensive and time‐consuming. Here, a high‐throughput strategy is proposed for screening buffer layer parameters. Taking the epitaxial growth of PbZr_1‐xTi_xO₃ ferroelectric films as a model system, the optimal thickness of the CoFe₂O₄ buffer layer is successfully determined, enabling the epitaxial growth of [111]‐oriented PbZr_0.2Ti_0.8O₃ on a [001]‐oriented Mica substrate. Furthermore, a composite buffer layer structure consisting of SrRuO₃ and CoFe₂O₄ is screened, which facilitated the epitaxial growth of [111]‐oriented PbZr_1‐xTi_xO₃ films on a [001]‐oriented SrTiO₃ substrate. This work establishes an efficient approach for the high‐throughput screening of buffer layer structures and provides valuable insights into the design of epitaxial functional thin films beyond conventional substrate constraints.

Negative capacitance effects with fast response times hold great potential for reducing the power consumption in high-frequency nanoelectronics. Nevertheless, the negative capacitance effect faces considerable complexity arising from the dynamic interplay among electrostatic, nucleation energies, and domain evolution. This intricate balance poses a formidable challenge to achieving fast negative capacitance. Herein, we have achieved a fast negative capacitance time of ∼16.23 ns in PbZr_0.2Ti_0.8O₃ (PZT) thin film, and our investigation confirms the presence of acicular ferroelastic domains within the PZT thin film. Under reversal electric fields, these acicular ferroelastic domains undergo a unique flipping process, transitioning through domain expansion and contraction. This distinct domain flipping manner accelerates the nucleation and growth of ferroelectric domains, thereby facilitating the observed fast negative capacitance. The realization of fast negative capacitance holds substantial promise for reducing operational time and power consumption, offering prospects for the design of nanoelectronics with significantly lower power requirements.

Metal halide perovskites have emerged as promising materials for X-ray detection due to their high X-ray attenuation coefficients, defect tolerance, and suitability for large-area, low-temperature fabrication. However, the intrinsic high ion conductivity of these materials presents challenges, such as high dark current density and current drift, which impair the stability and sensitivity of perovskite X-ray detectors. This study introduces an approach to mitigating these issues by incorporating 2,2,3,3,3-pentafluoropropylamine hydrochloride (PFH) into polycrystalline MAPbI_3-xCl_x films using a one-step blade-coating method. PFH aggregates at grain boundaries, raising local vacuum energy levels and passivating surface defects, thereby reducing ion conductivity without affecting electron conductivity. As a result, this approach significantly reduces the dark current and enhances sensitivity, achieving a low detection limit of 14.7 nGy_air/s. Additionally, it improves signal stability, consistency, and response speed of the detector. These findings suggest that PFH is a promising additive for advancing the performance and practical application of polycrystalline metal halide perovskite-based X-ray detectors.