Advanced Physics Research最新文献

Emerging Cellulose Ionogels

Through the physical construction of molecular network structures, soft gel materials derived from biomass cellulose can acquire a range of distinctive properties and be used in high-value applications. Article number 2500020 by Xiaoyu Guo, Suqing Zeng, Dawei Zhao and co-workers explores the design of functional gels through molecular-scale physical enhancement methods, thereby broadening the potential applications of cellulose gels in emerging flexible electronics. The integration of attractive physical processing techniques with molecular-scale design represents a promising research avenue for cellulose gels. This study provides valuable insights for the future development of smart gels and wearable devices.

Sloppiness Consistency Drives Balance in Mechanical Modeling

The study by Wenyang Liu, Shujuan Hou and co-workers (see article number 2500002) introduces an information-geometry-based approach for simplifying biomechanical constitutive models. By analyzing parameter sensitivity matrices, it reveals the inherent “sloppiness” of soft tissue models and constructs a parameter hyperspace with a four-step optimization strategy to reduce model complexity while maintaining identifiability and predictive accuracy, as successfully demonstrated in brain tissue and patellar tendon models.

Localizing optical fields at deep sub-wavelength scales has applications in ultra-strong light-matter interactions and in efficient coupling to quantum emitters. Surface plasmon polaritons can be confined within and on the surfaces of nanostructures on spatial scales of only a few nanometers. However, they generally suffer from significant dissipation. Porous gold nanosponges and percolated thin films demonstrate an interestingly highly-localized plasmonic feature with an enhancement factor and quality factor beyond what is achievable with localized plasmons in nanostructures. Here, the characteristics of plasmon resonances in porous gold nanoparticles are explored using cathodoluminescence spectroscopy. It is demonstrated that visible light can be localized inside the nanosponges at spatial scales as small as 20 nm, forming dipole-like resonances. Moreover, it is shown that at specific wavelengths the entire structure supports a collective resonance, with the emitted light exhibiting polarization that represents an average over all possible dipolar emission directions. The analysis demonstrates the potential of gold nanosponges for exploring the intricate physics of localized resonances and their collective responses, and it paves the way toward their applications in controlling emissions from quantum emitters.

Carbon fiber and other fibrous composites are widely used in structural components for wind turbines and aircraft. These applications not only require high strength and low weight but also tailored electrical properties. Designing new composites that can resist lightning strikes or be used in bioelectronics relies on accurately predicting their electrical conductivities. Yet most models of conductivity in these composites lack a geometrically meaningful basis, particularly if applied far from the percolation threshold which often occurs in the earliest 1% of the composite design space. An electrical model that is grounded in real fiber geometries and arrangements is derived. New equations are obtained, combining materials science and network physics, that accurately predict individual fiber overlap, neighbor distributions, and percolation thresholds in systems of overlapping shapes. Combining these equations with the new electrical model of a “foamy cluster”, yielded excellent predictions of conductivity in many different types of fibrous composites.

Superconducting Josephson structures play a significant role in quantum-state engineering. Achieving high-fidelity quantum state measurements in superconducting Josephson structures requires ultra-low noise environments and robust signal purification techniques. Here, the advanced low-noise signal measurement system designed for dilution refrigerators is presented, integrating multi-stage cryogenic filtering and electromagnetic shielding strategies to suppress noise sources across a broad frequency spectrum. The effectiveness of low-pass RC filters is demonstrated, silver-epoxy microwave absorbers, and optimized ground isolation to achieve an unprecedented noise reduction, enabling sub-nanoampere switching current distribution measurements superior to commerical systems at mK temperatures. The system is optimized for precision studies of superconductor-insulator-superconductor, superconductor-ferromagnet-superconductor, and superconductor-normal metal-superconductor Josephson junctions with low critical currents. This approach establishes a reliable framework for next-generation quantum electronic experiments, ensuring that observed switching phenomena are governed by intrinsic device physics rather than environmental perturbations.

Due to the large size of sodium ions and their slow redox kinetics in electrochemical processes, the sodium ion batteries currently are still far from satisfactory. This study investigates the electrical transport properties of ReNiO₂/ Ti₃C₂ heterojunctions in sodium ion batteries through a combination of first principles calculations and machine learning analysis. The ReNiO₂/Ti₃C₂ heterojunctions exhibit metallic characteristics and enhanced electronic conductivity due to the hybridization of p-d orbitals and the strengthening of Ni─Ti metal bonds. The sodium ion migration energy barrier decreases with increasing rare earth atomic number, facilitating ion transport. Machine learning analysis identifies key factors influencing ion and electron transport rates, including strain, lattice constants, and doping concentration. These findings provide theoretical guidance for designing more efficient negative electrodes for sodium ion batteries.

Quantum materials provide a fertile ground in which to test and realize unusual phenomena such as quantum anomalies predicted by quantum field theory. There are three important symmetries that are broken when classical field theory is moved into the quantum regime, the scale anomaly, the axial (chiral) anomaly, and the parity anomaly. Several potential device applications may be realized by the discovery of quantum anomalies in condensed matter, enabled by the new physics they embody, including ultra-sensitive dark matter detectors, far infrared optical modulators, micro-bolometric detectors, low-dissipation ballistic transporters, terahertz-based qubits, terahertz polarization state controls, passive magnetic field sensors, stable topological superconductors that host Majorana fermions, and qubits topologically protected against decoherence. In this perspective article, the definition of these quantum anomalies is laid out, how little is known in the context of condensed matter, and how quantum anomalies are predicted to manifest as anomalous electronic, thermal, and magnetic behavior in experiments on topological quantum materials, including Weyl and Dirac semimetals. Furthermore, the importance that mechanical strain and defects will play in modifying signatures of quantum anomalies is discussed.

The propagation of antiphase boundaries (APBs) and threading dislocations (TDs) poses a significant impediment to the realisation of high-quality group III–V semiconductors grown on group IV platforms. The complete annihilation of APBs and a substantial reduction in threading dislocation density (TDD) are essential for achieving high-efficiency III–V devices compatible with complementary metal-oxide semiconductor (CMOS) technology. In this study, a novel growth technique is proposed and developed to fabricate a faceted germanium (Ge) buffer on a discontinuous (111)-faceted V-groove silicon (Si) substrate with a 500 nm flat ridge width. Subsequently, a GaAs buffer is grown on the Ge/V-groove Si virtual substrate using a ramped temperature growth process to minimise the prevalence of line and planar defects in the buffer structure. An APB-free GaAs buffer is successfully achieved, as confirmed by cross-sectional and plan-view transmission electron microscopy (TEM) and atomic force microscopy (AFM) analyses. The faceted Ge buffer layer obtained through this innovative approach alleviates the stringent fabrication requirements and intricate processing typically associated with conventional continuous V-groove Si substrates. This advancement facilitates the development of photonic integrated circuits by providing a simplified and efficient alternative substrate solution.