Advanced Physics Research最新文献

Resistive switching memory has emerged as a promising candidate for next-generation data storage and is regarded as a key enabler for the advancement of artificial intelligence technologies. However, conventional resistive memory architectures face critical challenges, including sneak-path current interference, poor scalability, and limited integration density, which hinder their practical deployment in high-density neuromorphic systems. In this study, a self-rectifying 3D 2 × 2 crossbar array based on a diode–memristor–diode (DMD) architecture using a Pt/SrMnO₃/Pt configuration is demonstrated for the first time, exhibiting excellent electrical performance and outstanding operational stability. The device effectively suppresses sneak-path currents, thereby enabling the integration of high-density memory arrays. The reset process is quantitatively analyzed through machine learning applied to electrical transport characteristics, while the high-resistance state is accurately described using the Poisson–Boltzmann formalism. These results highlight the significant potential of the stacked Pt/SrMnO₃/Pt structure for next-generation non-volatile memory and provide a solid foundation for its application in neuromorphic computing and artificial neural networks.

This study explores the integration of atomic layer deposited (ALD) HfO₂ dielectric films with solution-processed In₂O₃ semiconductor channel, thin-film transistors (TFTs) for a silicon chip-free temperature sensor label. The inclusion of the HfO₂ high-κ dielectric permits reduced voltage operation of the sensor label. HfO₂ films are deposited by atomic layer deposition (ALD) at three different hot source temperatures (80°C, 90°C, 100°C), with XPS revealing improved stoichiometry and O/Hf ratios of 1.75, 1.92, and 1.95, respectively, as temperature increases. MOSCAP measurements show improved oxide/semiconductor interface with higher deposition temperatures. The extracted dielectric constants (ε_r ≈ 18.5–18.8) correspond to an equivalent oxide thickness (EOT) of about 3.1 nm, consistent with optimized high-κ film formation. To enhance drain current, a reduced 7.5 nm HfO₂ film thickness is used, achieving higher current but reducing yield by 30% due to increased leakage probability in ultrathin films. A voltage divider circuit is developed to integrate an electrochemical thermal sensor, TFT, and an irreversible visual indicator (IVI), allowing for temperature monitoring with a resistivity change of three orders of magnitude at 8°C. The circuit is powered by a 60 mF supercapacitor array providing approximately 0.21 J of available energy, resulting in IVI activation within 40 min at measured activation currents of 20 µA. The system demonstrates potential for low-voltage, energy-efficient, silicon-free sensor labels in applications such as food safety and healthcare monitoring.

Liquid metals possess excellent electrical conductivity, fluidity, and high density, exhibiting unique electroresponsive characteristics under applied electric fields. This article systematically investigates the instantaneous response, frequency synchronization, and resonance phenomena of gallium-based liquid metal droplets under square-wave alternating electric fields. We comprehensively clarify the effects of droplet volume, alloy composition, electric field intensity, and mechanical confinement on electrically induced resonance behavior. In free spaces, we reveal a critical transition in governing laws characterized by the modified Bond number (Bo_m) as the dimensionless parameter. We observe coordinated linear responses of transverse and longitudinal amplitudes to applied electric field amplitude for liquid metal droplets with Bo_m < 1, while droplets with Bo_m > 1 exhibit nonlinear responses featuring asymmetric deformation and multi-modal transitions. Within confined channels, droplets display multi-mode standing wave patterns, with the number of surface wave crests correlating with droplet volume. Multi-droplet systems display collective dynamics modulated by array size and the spatial positioning of droplets within the collective. These findings establish theoretical foundations for controlling and amplifying the electrically induced behavior of positionally stable liquid metal droplets, and open new pathways for developing liquid metal resonance-based multi-excitation point mixers, flexible actuators, and reconfigurable electronic systems.

Transition metal penta-tellurides, ZrTe₅ and HfTe₅ have recently drawn a lot of attention due to their fascinating physical properties and for being prominent materials showing topological phase transitions. In this work, we present first in-depth investigation of elasto-mechanical, thermophysical, and optical properties of these compounds. In particular, we analyzed the directional dependence of the elastic properties, explored the optical response for different photon polarization directions and examined previously unreported potential industrial applications of these materials. We also studied their electronic and topological properties. We used Density Functional Theory (DFT) based calculations to study all of these properties. This study suggests that the materials are mechanically stable, possess high mechanical and bondinganisotropy, are soft and brittle in nature. Investigation of thermophysical properties indicates weak bonding strength in these compounds and suggests their possible application in acoustic and thermoelectric devices. Examination of their optical characteristics reveals that they have high refractive indices at low energy. They are very good ultraviolate absorbers and potential candidates for solar coating devices. Our study also reveals that these materials show characteristics of weak ℤ₂ topological insulators. Spin-orbit interaction is responsible for enhancing energy gaps and promoting insulating characteristics in these compounds.

Monolayers of transition metal dichacogenides (1L-TMDs) show strong second-order nonlinearity and symmetry-driven selection rules from their threefold lattice symmetry. This process resembles the valley-contrasting selection rules for photoluminescence (PL) in these materials. However, the underlying physical mechanisms fundamentally differ since second harmonic generation (SHG) is a coherent process, whereas PL is incoherent, leading to distinct interactions with photonic nanoresonators. In this study, the far-field circular polarization properties of SHG from MoS₂ monolayers resonantly interacting with spherical gold nanoparticles were investigated. The results indicate that the coherence of the second harmonic allows its polarization to be mostly preserved, unlike in an incoherent process, where the polarization is scrambled. These findings provide important insights for future applications in valleytronics and quantum nanooptics, where both coherent and incoherent processes can be probed in such hybrid systems without altering sample geometry or operational wavelength.

Metal–organic frameworks (MOFs) present a unique class of crystalline materials with programmable architectures that enable precise control over dielectric behavior. Their well-defined metal nodes, organic linkers, and porous structures facilitate polarization mechanisms, critical for high-performance dielectrics. The beauties of the architectural design strategies from homogeneous MOFs, phase-engineered heterogeneous MOFs, MOFs incorporated into polymer matrices as fillers for low dielectric loss, stimuli-responsive MOFs, and conductive MOFs are systematically analyzed to reveal the fundamental interplay between framework structure, charge dynamics, and dielectric functionality. Importantly, their intrinsic structural regularity and defect control support high breakdown strength through deep trap states and uniform electric field distribution. Last but not least, the prospects of MOFs such as device-level integration, hybridization with 2D materials, and machine learning to connect structure-polarizability relationships and address their key state-of-the-art challenges are discussed.

We report on optimizing the spectral purity of heralded single photons in the telecom O-band, where single photons can be propagated with low loss and low dispersion in a standard telecom optical fiber. We numerically searched for various group-velocity-matching conditions and corresponding optimal poling structures of a potassium titanyl phosphate crystal for spontaneous parametric downconversion. Our poling optimization results using phase-matching coherence-length and sub-coherence-length modulation schemes show $$% spectral purity with pump wavelengths ranging from 603.8 to 887.3 nm. Some optimized configurations are feasible with off-the-shelf lasers and single-photon detectors. Moreover, by investigating noise photon spectra for different poling optimization methods, we show that, in practice, appropriate, gentle spectral filtering helps achieve high purity. This study will pave the way for developing practical quantum sources for quantum information applications at the telecom O-band.

In the past decades, carbon nanowalls (CNWs) have attracted great interest due to their specific electronic structure and morphology suitable for optoelectronic, photo- and electrochemical systems. This report presents a comparative study on the growth of CNWs on various substrates–quartz (SiO₂), stainless steel (SS304), tantalum (Ta), and titanium (Ti) using the capacitively coupled plasma-enhanced chemical vapor deposition (CCP-PECVD). It is found that the substrate properties significantly influence the morphology, degree of graphitization, and electrochemical characteristics of the CNWs. SiO₂ provides the lowest defect density and highest structural order, while Ta and Ti promote accelerated CNWs growth due to their high thermal conductivity. Electrochemical tests reveal pronounced photoelectrochemical activity of the CNWs, especially on metallic substrates. Impedance spectroscopy indicates an increase in the electrochemical activity after CNWs growth. The results highlight the importance of substrate selection for controlling the structural and functional properties of the CNWs.

The device performance of Cu–In–Zn–S (CIZS)-based quantum-dot light-emitting diodes (QLEDs) still lags far behind CdSe-based QLEDs, which mainly arise from unique trap-related recombination in the CIZS quantum dots (QDs). Herein, the carrier dynamics behavior of CIZS-based and CdSe-based QLEDs was studied by transient electroluminescence (TrEL) technology, and the difference in the falling edge of the TrEL response was obviously observed in both QLEDs. The results show that Cu-related defect states (Cu-states) created a substantial hole injection barrier, making traditional hole-transport layer modifications ineffective for carrier injection and transport balance. By engineering the ZnO electron transport layer (ETL), the electron injection and transport were reduced, which suppressed trap-state-mediated non-radiative recombination. At last, carrier dynamics models were proposed to clarify the phenomenon of falling edge overshoot in the CIZS-based QLEDs. This approach overcomes the intrinsic hole transport limitation in CIZS QDs caused by Cu-states, offering a viable method to balance the carrier injection and transport without enhancing hole injection.

The rapid and accurate detection of viral biomarkers is critical for controlling infectious disease outbreaks, as highlighted by the COVID-19 pandemic. Here, we present a label-free platform for the ultrasensitive detection of SARS-CoV-2 spike protein and IgG antibodies in liquid using surface-enhanced Raman spectroscopy (SERS) based on an array of plasmonic H-shaped nano-apertures. The nanostructure is designed to support a resonance at 777.8 nm. The Raman signal of both biomolecules was recorded at several locations on the nanostructure under off-resonance laser excitation at 785 nm, confirming its reproducibility. The designed nanostructure enables limit of detection of 0.85 ng/mL in a liquid environment, without the need for complex surface functionalization or labeling. Using principal component analysis (PCA), we successfully distinguished between spike protein, IgG antibodies, and their mixtures, highlighting the platform's ability to analyze complex biological matrices. This work advances the development of sensitive SERS-based biosensors for the rapid and accurate detection of emerging pathogens in liquid environments.