Broadband spin-dependent anti-reflection in chiral time-varying metamaterials.

Time-varying metamaterials have garnered significant attention for their ability to achieve anti-reflection in the time domain. However, current systems face limitations in spin-controlled manipulation, as most studies focus on non-chiral, time-varying metamaterials. Consequently, realizing spin-dependent broadband anti-reflection using time-varying chiral metamaterials remains underexplored.

Magneto-optical metasurfaces for high-Q perfect absorption with quasi-bound states in the continuum.

We present a novel, to the best of our knowledge, magneto-optical (MO) metasurface composed of a bismuth iron garnet (BIG) nanocube array, designed to achieve near-perfect absorption through quasi-bound states in the continuum (QBICs). This metasurface supports a stable QBIC mode induced by MO-induced permittivity terms that break the symmetry of the permittivity tensors, corresponding to a longitudinal electric dipole (ED) mode. By integrating graphene to introduce material loss, the absorption reaches 99.

Tracing phosphorus sources in the river-lake system using the oxygen isotope of phosphate.

The biogeochemical cycling of phosphorus (P) in river-lake systems presents significant challenges in tracing P sources, highlighting the importance of effective traceability approaches for formulating targeted management measures to mitigate lake eutrophication. In this study, we used the oxygen isotope of phosphate (δO) as a tracer in the river-lake systems, establishing a tracing pathway from potential end-members, through inflow rivers, and eventually to the lake. Taking Dianshan Lake and its main inflow rivers as the study area, we measured δO values of potential end-members, including domestic sewage treatment plant effluents, industrial effluents from phosphorus-related enterprises (printing and dyeing, electroplating, plastics, etc.

Dual-band high-Q near-perfect absorption by tilted Si-assisted metasurfaces.

All-dielectric metasurface perfect absorbers (MPAs) based on quasibound states in the continuum (QBICs) play a crucial role in optical and photonic devices as they can excite high-Q resonances. These structures require adding back reflectors or placing at least two asymmetric elements in each unit to break the absorption limit of 50%, which will increase the design complexity. In this work, we propose a high-Q monolayer MPA (MMPA) composed of a tilted Si nanocube array.

Near-perfect absorption of a honeycomb metasurface through QBICs.

All-dielectric high-Q metasurface absorbers based on quasi-bound states in the continuum (QBICs) are essential for optical and photonic devices. However, achieving perfect absorption requires adding back reflectors at the bottom or placing at least four asymmetric elements in each unit of monolayer metasurfaces, which will increase the design complexity. This work proposes a honeycomb structure with units periodically arranged as a hexagonal lattice.

Optical analogy for temporal diffraction in tight-binding lattice.

The wave propagating through the temporal boundary has attracted considerable attention in the past few years because of the potential applications of time-varying systems in the optics community. However, temporal diffraction of light remains to be investigated, because free space is non-dispersive. Here, we theoretically provide the analytical expressions for the temporal diffraction contributions of electron waves across the temporal boundary between the free space and a dispersive medium.

Pain and Self-Management Status Among Chinese Patients With Cancer During the COVID-19 Pandemic.

Background: To investigate the pain and self-management status of patients with cancer and the influencing factors of pain and self-management status during the COVID-19 pandemic.

Methods: A cross-sectional design was used. Eighty-one Chinese patients with cancer were recruited in December 2020.

Author Correction: Modelling of free-form conformal metasurfaces.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Extreme In-Plane Thermal Conductivity Anisotropy in Titanium Trisulfide Caused by Heat-Carrying Optical Phonons.

High in-plane anisotropies arise in layered materials with large structural difference along different in-plane directions. We report an extreme case in layered TiS, which features tightly bonded atomic chains along the -axis direction, held together by weaker, interchain bonding along the -axis direction. Experiments show thermal conductivity along the chain twice as high as between the chain, an in-plane anisotropy higher than any other layered materials measured to date.

Phase Transition across Anisotropic NbS and Direct Gap Semiconductor TiS at Nominal Titanium Alloying Limit.

Alloying selected layered transitional metal trichalcogenides (TMTCs) with unique chain-like structures offers the opportunities for structural, optical, and electrical engineering thus expands the regime of this class of pseudo-one-dimensional materials. Here, the novel phase transition in anisotropic Nb Ti S alloys is demonstrated for the first time. Results show that Nb Ti S can be fully alloyed across the entire composition range from triclinic-phase NbS to monoclinic-phase TiS .

Anomalous phase transition behavior in hydrothermal grown layered tellurene.

Recent studies have demonstrated that tellurene is a van der Waals (vdW) two-dimensional material with potential optoelectronic and thermoelectric applications as a result of its pseudo-one-dimensional structure and properties. Here, we report on the pressure induced anomalous phase transition of tellurium nanoribbons. The observation of clean phase transitions was made possible with high quality single crystalline Te nanoribbons that are synthesized by hydrothermal reaction growth.

Highly Sensitive Polarization Photodetection Using a Pseudo-One-Dimensional NbTi S Alloy.

Low-symmetry layered two-dimensional (2D) materials with strong in-plane optical anisotropy can potentially be applied for polarization photodetection. This is especially true for those 2D materials with a direct band gap, which can efficiently absorb light with specific axial polarization. However, discovering such new anisotropic 2D materials with a direct band structure is still extremely challenging.

Modelling of free-form conformal metasurfaces.

Artificial electromagnetic surfaces, metasurfaces, control light in the desired manner through the introduction of abrupt changes of electromagnetic fields at interfaces. Current modelling of metasurfaces successfully exploits generalised sheet transition conditions (GSTCs), a set of boundary conditions that account for electric and magnetic metasurface-induced optical responses. GSTCs are powerful theoretical tools but they are not readily applicable for arbitrarily shaped metasurfaces.

Mathematical deep learning for pose and binding affinity prediction and ranking in D3R Grand Challenges.

Advanced mathematics, such as multiscale weighted colored subgraph and element specific persistent homology, and machine learning including deep neural networks were integrated to construct mathematical deep learning models for pose and binding affinity prediction and ranking in the last two D3R Grand Challenges in computer-aided drug design and discovery. D3R Grand Challenge 2 focused on the pose prediction, binding affinity ranking and free energy prediction for Farnesoid X receptor ligands. Our models obtained the top place in absolute free energy prediction for free energy set 1 in stage 2.

Anomalous isoelectronic chalcogen rejection in 2D anisotropic vdW TiSSe trichalcogenides.

Alloying in semiconductors has enabled many civilian technologies in electronics, optoelectronics, photonics, and others. While the alloying phenomenon is well established in traditional bulk semiconductors owing to a vast array of available ternary phase diagrams, alloying in 2D materials still remains at its seminal stages. This is especially true for transition metal trichalcogenides (TMTCs) such as TiS3 which has been recently predicted to be a direct gap, high carrier mobility, pseudo-1D semiconductor.

In-Plane Optical Anisotropy and Linear Dichroism in Low-Symmetry Layered TlSe.

In-plane anisotropy of layered materials adds another dimension to their applications, opening up avenues in diverse angle-resolved devices. However, to fulfill a strong inherent in-plane anisotropy in layered materials still poses a significant challenge, as it often requires a low-symmetry nature of layered materials. Here, we report the fabrication of a member of layered semiconducting AB compounds, TlSe, that possesses a low-symmetry tetragonal structure and investigate its anisotropic light-matter interactions.

Abnormal band bowing effects in phase instability crossover region of GaSeTe nanomaterials.

Akin to the enormous number of discoveries made through traditional semiconductor alloys, alloying selected 2D semiconductors enables engineering of their electronic structure for a wide range of new applications. 2D alloys have been demonstrated when two components crystallized in the same phase, and their bandgaps displayed predictable monotonic variation. By stabilizing previously unobserved compositions and phases of GaSeTe at nanoscales on GaAs(111), we demonstrate abnormal band bowing effects and phase instability region when components crystallize in different phases.

TopP-S: Persistent homology-based multi-task deep neural networks for simultaneous predictions of partition coefficient and aqueous solubility.

Aqueous solubility and partition coefficient are important physical properties of small molecules. Accurate theoretical prediction of aqueous solubility and partition coefficient plays an important role in drug design and discovery. The prediction accuracy depends crucially on molecular descriptors which are typically derived from a theoretical understanding of the chemistry and physics of small molecules.

Quantitative Toxicity Prediction Using Topology Based Multitask Deep Neural Networks.

The understanding of toxicity is of paramount importance to human health and environmental protection. Quantitative toxicity analysis has become a new standard in the field. This work introduces element specific persistent homology (ESPH), an algebraic topology approach, for quantitative toxicity prediction.

Breaking the polar-nonpolar division in solvation free energy prediction.

Implicit solvent models divide solvation free energies into polar and nonpolar additive contributions, whereas polar and nonpolar interactions are inseparable and nonadditive. We present a feature functional theory (FFT) framework to break this ad hoc division. The essential ideas of FFT are as follows: (i) representability assumption: there exists a microscopic feature vector that can uniquely characterize and distinguish one molecule from another; (ii) feature-function relationship assumption: the macroscopic features, including solvation free energy, of a molecule is a functional of microscopic feature vectors; and (iii) similarity assumption: molecules with similar microscopic features have similar macroscopic properties, such as solvation free energies.

Controlling Structural Anisotropy of Anisotropic 2D Layers in Pseudo-1D/2D Material Heterojunctions.

Chemical vapor deposition and growth dynamics of highly anisotropic 2D lateral heterojunctions between pseudo-1D ReS and isotropic WS monolayers are reported for the first time. Constituent ReS and WS layers have vastly different atomic structure, crystallizing in anisotropic 1T' and isotropic 2H phases, respectively. Through high-resolution scanning transmission electron microscopy, electron energy loss spectroscopy, and angle-resolved Raman spectroscopy, this study is able to provide the very first atomic look at intimate interfaces between these dissimilar 2D materials.

Angle resolved vibrational properties of anisotropic transition metal trichalcogenide nanosheets.

Layered transition metal trichalcogenides (TMTCs) are a new class of anisotropic two-dimensional materials that exhibit quasi-1D behavior. This property stems from their unique highly anisotropic crystal structure where vastly different material properties can be attained from different crystal directions. Here, we employ density functional theory predictions, atomic force microscopy, and angle-resolved Raman spectroscopy to investigate their fundamental vibrational properties which differ significantly from other 2D systems and to establish a method in identifying anisotropy direction of different types of TMTCs.

Controlling the Geometries of Si Nanowires through Tunable Nanosphere Lithography.

A tunable nanosphere lithography (NSL) technique is combined with metal-assisted etching of silicon (Si) to fabricate ordered, high-aspect-ratio Si nanowires. Non-close-packed structures are directly prepared via shear-induced ordering of the nanospheres. The spacing between the nanospheres is independent of their diameters and tuned by changing the loading of nanospheres.

Two-dimensional Fibonacci grating for far-field super-resolution imaging.

A two-dimensional (2D) Fibonacci grating is used to transform evanescent waves into propagating waves for far-field super-resolution imaging. By detecting far-field intensity distributions of light field through objects in front of the 2D Fibonacci grating in free space at once, we can retrieve the image of objects with beyond λ/7 spatial resolution. We also find that the coherent illumination case can give a better resolution than incoherent illumination case by such 2D grating-assisted imaging system.

Strong dichroic emission in the pseudo one dimensional material ZrS.

Zirconium trisulphide (ZrS), a member of the layered transition metal trichalcogenides (TMTCs) family, has been studied by angle-resolved photoluminescence spectroscopy (ARPLS). The synthesized ZrS layers possess a pseudo one-dimensional nature where each layer consists of ZrS chains extending along the b-lattice direction. Our results show that the optical properties of few-layered ZrS are highly anisotropic as evidenced by large PL intensity variation with the polarization direction.