Sub-nanosecond polarization switching with anomalous kinetics in vdW ferroelectric WTe.

Recently discovered "sliding ferroelectrics" exhibit distinct polarization origin and switching mechanism compared to conventional ferroelectric materials. However, a clear understanding of the polarization switching kinetics remains lacking. Here, we demonstrate sub-nanosecond (0.

Orbital Order Triggered Out-of-Plane Ferroelectricity in Magnetic Transition Metal Dihalide Monolayers.

Despite decades of multiferroic research, orbital-order-driven ferroelectricity remains exceptionally rare. Here, we demonstrate spontaneous out-of-plane ferroelectric polarization in monolayer magnetic transition-metal dihalides through first-principles calculations. Partially occupied d-orbitals in edge-sharing octahedra stabilize two-dimensional spatial orbital order, breaking inversion symmetry to induce coupled electronic and ionic polarization perpendicular to the plane.

Case report: a case of R0 resection in a patient with PD-L1-negative, microsatellite-stabilized advanced pancreatic cancer after down-stage treatment with a PD-1 inhibitor in combination with chemotherapy.

Background: Pancreatic ductal adenocarcinoma (PDAC) is a gastrointestinal tumor with high morbidity and mortality. Despite advances in diagnostic and therapeutic modalities, the outcome and prognosis of PDAC remain poor. Most patients have locally advanced disease (30%-35%) or distant metastases (50%-55%) at the time of diagnosis.

Super strain enhanced thermal conductivity of monolayer aluminum/gallium nitride (AlGaN) alloys.

The AlGaN alloys play a crucial role as buffer layers in next-generation power electronic devices, where thermal transport is of great significance to performance stability and reliability. Typically, the AlGaN alloys are often subjected to stress, stemming from various factors such as material preparation processes, temperature fluctuations during device operation, and external mechanical forces. Nevertheless, how to regulate stress and the impact of stress on the thermal transport properties of AlGaN alloys remain unclear.

Intrinsic Breakdown Strength: Theoretical Derivation and First-Principles Calculations.

Intrinsic breakdown strength (F_{bd}), as the theoretical upper limit of electric field strength that a material can sustain, plays important roles in determining dielectric and safety performance. The well accepted concept is that a larger band gap (E_{g}) often leads to a larger intrinsic breakdown strength. In this work, we analytically derive a simplified model of F_{bd}, showing a linear relationship between F_{bd} and the maximum electron density of states (DOS_{max}) within the energy range spanning from the conduction band minimum (CBM) to CBM+E_{g}.

Mechanism of Type-II Multiferroicity in Pure and Al-Doped CuFeO_{2}.

Type-II multiferroicity, where electric polarization is induced by specific spin patterns, is crucial in fundamental physics and advanced spintronics. However, the spin model and magnetoelectric coupling mechanisms in prototypical type-II multiferroic CuFeO_{2} and Al-doped CuFeO_{2} remain unclear. Here, by considering both spin and alloy degrees of freedom, we develop a magnetic cluster expansion method, which considers all symmetry allowed interactions.

Advancing nonadiabatic molecular dynamics simulations in solids with E(3) equivariant deep neural hamiltonians.

Non-adiabatic molecular dynamics (NAMD) simulations have become an indispensable tool for investigating excited-state dynamics in solids. In this work, we propose a general framework, NAMD (Neural-Network Non-Adiabatic Molecular Dynamics), which employs an E(3)-equivariant deep neural Hamiltonian to boost the accuracy and efficiency of NAMD simulations. Distinct from conventional machine learning methods that predict key quantities in NAMD, NAMD computes these quantities directly with a deep neural Hamiltonian, ensuring excellent accuracy, efficiency, and consistency.

Tunable Ultrafast Charge Transfer across Homojunction Interface.

Charge transfer at heterojunction interfaces is a fundamental process that plays a crucial role in modern electronic and photonic devices. The essence of such charge transfer lies in the band offset, making charge transfer uncommon in a homojunction. Recently, sliding ferroelectricity has been proposed and confirmed in two-dimensional van der Waals stacked materials such as bilayer boron nitride.

Accelerating the calculation of electron-phonon coupling strength with machine learning.

The calculation of electron-phonon couplings (EPCs) is essential for understanding various fundamental physical properties, including electrical transport, optical and superconducting behaviors in materials. However, obtaining EPCs through fully first-principles methods is notably challenging, particularly for large systems or when employing advanced functionals. Here we introduce a machine learning framework to accelerate EPC calculations by utilizing atomic orbital-based Hamiltonian matrices and gradients predicted by an equivariant graph neural network.

Atomistic Origin of Diverse Charge Density Wave States in CsV_{3}Sb_{5}.

Kagome metals AV_{3}Sb_{5} (A=K, Rb, or Cs) exhibit intriguing charge density wave (CDW) instabilities, which interplay with superconductivity and band topology. However, despite firm observations, the atomistic origins of the CDW phases, as well as hidden instabilities, remain elusive. Here, we adopt our newly developed symmetry-adapted cluster expansion method to construct a first-principles-based effective Hamiltonian of CsV_{3}Sb_{5}, which not only reproduces the established inverse star of David (ISD) phase, but also predict a series of D_{3h}-n states under mild tensile strains.

Moiré magnetic exchange interactions in twisted magnets.

In addition to moiré superlattices, twisting can also generate moiré magnetic exchange interactions (MMEIs) in van der Waals magnets. However, owing to the extreme complexity and twist-angle-dependent sensitivity, all existing models fail to fully capture MMEIs and thus cannot provide an understanding of MMEI-induced physics. Here, we develop a microscopic moiré spin Hamiltonian that enables the effective description of MMEIs via a sliding-mapping approach in twisted magnets, as demonstrated in twisted bilayer CrI.

Flat-band based high-temperature ferromagnetic semiconducting state in the graphitic CN monolayer.

Half-filled isolated flat-band paves a new way to realize high-temperature ferromagnetic semiconductor for spintronics applications, but it is extremely rare in lattice models and lacking in realistic materials. Herein, the 2 × 2 super-cell of the honeycomb lattice with a single-hole defect is proposed as a new lattice model (HL-D-1/8) to realize nontrivial isolated flat-bands. We further demonstrate that CN monolayer of the experimentally realized graphitic carbon nitride (Adv.

Median arcuate ligament syndrome complicated with gallbladder stones: A case report.

Background: Median arcuate ligament syndrome (MALS) is a rare disease caused by compression of the celiac trunk artery by the median arcuate ligament (MAL). It can cause symptoms of postprandial abdominal pain, weight loss, and nausea and vomiting.

Case Summary: A 55-year-old woman was admitted due to abdominal pain, nausea and vomiting.

Out-of-plane ferroelectricity and robust magnetoelectricity in quasi-two-dimensional materials.

Thin-film ferroelectrics have been pursued for capacitive and nonvolatile memory devices. They rely on polarizations that are oriented in an out-of-plane direction to facilitate integration and addressability with complementary metal-oxide semiconductor architectures. The internal depolarization field, however, formed by surface charges can suppress the out-of-plane polarization in ultrathin ferroelectric films that could otherwise exhibit lower coercive fields and operate with lower power.

Toward Ultimate Memory with Single-Molecule Multiferroics.

The demand for high-density storage is urgent in the current era of data explosion. Recently, several single-molecule (-atom) magnets and ferroelectrics have been reported to be promising candidates for high-density storage. As another promising candidate, single-molecule multiferroics are not only small in size but also possess ferroelectric and magnetic orderings, which can sometimes be strongly coupled and used as data storage to realize the combination of electric writing and magnetic reading.

Realistic Spin Model for Multiferroic NiI_{2}.

A realistic first-principle-based spin Hamiltonian is constructed for the type-II multiferroic NiI_{2}, using a symmetry-adapted cluster expansion method. Besides single ion anisotropy and isotropic Heisenberg terms, this model further includes the Kitaev interaction and a biquadratic term, and can well reproduce striking features of the experimental helical ground state, that are, e.g.

A General Tensor Prediction Framework Based on Graph Neural Networks.

Graph neural networks (GNNs) have been shown to be extremely flexible and accurate in predicting the physical properties of molecules and crystals. However, traditional invariant GNNs are not compatible with directional properties, which currently limits their usage to the prediction of only invariant scalar properties. To address this issue, here we propose a general framework, i.

Pyrolytic Graphite for an In-Plane Force Study of Diamagnetic Levitation: A Potential Microdetector of Cracks in Magnetic Material.

The diamagnetic levitation technique can be applied in non-destructive testing for identifying cracks and defects in magnetic materials. Pyrolytic graphite is a material that can be leveraged in micromachines due to its no-power diamagnetic levitation on a permanent magnet (PM) array. However, the damping force applied to pyrolytic graphite prevents it from maintaining continuous motion along the PM array.

Theoretical study on the magnetic properties of cathode materials in the lithium-ion battery.

The layered LiMO (M = Co, Ni, and Mn) materials are commonly used as the cathode materials in the lithium-ion battery due to the distinctive layer structure for lithium extraction and insertion. Although their electrochemical properties have been extensively studied, the structural and magnetic properties of LiNiO are still under considerable debate, and the magnetic properties of monoclinic LiMnO are seldom reported. In this work, a detailed study of LiNiO, LiMnO, and a half-doped material LiNiMnO is performed via both first-principles calculations and Monte Carlo simulations based on the effective spin Hamiltonian model.

Significantly Enhanced Room-Temperature Ferromagnetism in Multiferroic EuFeO Thin Films.

Regulating the magnetic properties of multiferroics lays the foundation for their prospective application in spintronic devices. Single-phase multiferroics, such as rare-earth ferrites, are promising candidates; however, they typically exhibit weak magnetism at room temperature (RT). Here, we significantly boosted the RT ferromagnetism of a representative ferrite, EuFeO, by oxygen defect engineering.

Electronically phase separated nano-network in antiferromagnetic insulating LaMnO/PrMnO/CaMnO tricolor superlattice.

Strongly correlated materials often exhibit an electronic phase separation (EPS) phenomena whose domain pattern is random in nature. The ability to control the spatial arrangement of the electronic phases at microscopic scales is highly desirable for tailoring their macroscopic properties and/or designing novel electronic devices. Here we report the formation of EPS nanoscale network in a mono-atomically stacked LaMnO/CaMnO/PrMnO superlattice grown on SrTiO (STO) (001) substrate, which is known to have an antiferromagnetic (AFM) insulating ground state.

Case report: Two PD-L1 positive unresectable advanced pancreatic carcinoma patients with microsatellite stability achieved R0 resection after PD-1 antibody plus chemotherapy as a successful downstaging therapy: A report of two cases.

Background: Nonobvious early symptoms are a prominent characteristic of pancreatic cancer, resulting in only 20% of patients having resectable tumors at the time of diagnosis. The optimal management of unresectable advanced pancreatic cancer (UAPC) remains an open research question. In this study, the tumors shrank significantly after PD-1 antibody combined with chemotherapy in two UAPC patients, and both have achieved R0 (pathologically negative margin) resection and survival to date.

Two-Dimensional Organic-Inorganic Room-Temperature Multiferroics.

Organic-inorganic multiferroics are promising for the next generation of electronic devices. To date, dozens of organic-inorganic multiferroics have been reported; however, most of them show a magnetic Curie temperature much lower than room temperature, which drastically hampers their application. Here, by performing first-principles calculations and building effective model Hamiltonians, we reveal a molecular orbital-mediated magnetic coupling mechanism in two-dimensional Cr(pyz) (pyz = pyrazine) and the role that the valence state of the molecule plays in determining the magnetic coupling type between metal ions.

Convert Widespread Paraelectric Perovskite to Ferroelectrics.

While nature provides a plethora of perovskite materials, only a few exhibit large ferroelectricity and possibly multiferroicity. The majority of perovskite materials have the nonpolar CaTiO_{3}(CTO) structure, limiting the scope of their applications. Based on the effective Hamiltonian model as well as first-principles calculations, we propose a general thin-film design method to stabilize the functional BiFeO_{3}(BFO)-type structure, which is a common metastable structure in widespread CTO-type perovskite oxides.

Role of oxygen vacancies in colossal polarization in SmFeO thin films.

The orthorhombic rare-earth manganates and ferrites multiferroics are promising candidates for the next generation multistate spintronic devices. However, their ferroelectric polarization is small, and transition temperature is far below room temperature (RT). The improvement of ferroelectricity remains challenging.