1D Flat Bands in Phosphorene Nanoribbons with Pentagonal Nature.

Materials with flat bands can serve as a promising platform to investigate strongly interacting phenomena. However, experimental realization of ideal flat bands is mostly limited to artificial lattices or moiré systems. Here, a general way is reported to construct 1D flat bands in phosphorene nanoribbons (PNRs) with a pentagonal nature: penta-hexa-PNRs and penta-dodeca-PNRs, wherein the corresponding 1D flat bands are directly verified by using angle-resolved photoemission spectroscopy.

Superconductivity and nematic order in a new titanium-based kagome metal CsTiBi without charge density wave order.

The cascade of correlated topological quantum states in the newly discovered vanadium-based kagome superconductors, AVSb (A = K, Rb, and Cs), with a Z topological band structure has sparked immense interest. Here, we report the discovery of superconductivity and electronic nematic order in high-quality single-crystals of a new titanium-based kagome metal, CsTiBi, that preserves the translation symmetry, in stark contrast to the charge density wave superconductor AVSb. Transport and magnetic susceptibility measurements show superconductivity with an onset superconducting transition temperature T of approximately 4.

Van der Waals Electrides.

ConspectusElectrides make up a fascinating group of materials with unique physical and chemical properties. In these materials, excess electrons do not behave like normal electrons in metals or form any chemical bonds with atoms. Instead, they "float" freely in the gaps within the material's structure, acting like negatively charged particles called anions (see the graph).

Non-centrosymmetric topological phase probed by non-linear Hall effect.

Non-centrosymmetric topological material has attracted intense attention due to its superior characteristics as compared with the centrosymmetric one, although probing the local quantum geometry in non-centrosymmetric topological material remains challenging. The non-linear Hall (NLH) effect provides an ideal tool to investigate the local quantum geometry. Here, we report a non-centrosymmetric topological phase in ZrTe, probed by using the NLH effect.

A versatile model with three-dimensional triangular lattice for unconventional transport and various topological effects.

The finite Berry curvature in topological materials can induce many subtle phenomena, such as the anomalous Hall effect (AHE), spin Hall effect (SHE), anomalous Nernst effect (ANE), non-linear Hall effect (NLHE) and bulk photovoltaic effects. To explore these novel physics as well as their connection and coupling, a precise and effective model should be developed. Here, we propose such a versatile model-a 3D triangular lattice with alternating hopping parameters, which can yield various topological phases, including kagome bands, triply degenerate fermions, double Weyl semimetals and so on.

Superconducting, Topological, and Transport Properties of Kagome Metals CsTiBi and RbTiBi.

The recently discovered ATiBi (A=Cs, Rb) exhibit intriguing quantum phenomena including superconductivity, electronic nematicity, and abundant topological states. ATiBi present promising platforms for studying kagome superconductivity, band topology, and charge orders in parallel with AVSb. In this work, we comprehensively analyze various properties of ATiBi covering superconductivity under pressure and doping, band topology under pressure, thermal conductivity, heat capacity, electrical resistance, and spin Hall conductivity (SHC) using first-principles calculations.

Interplay of the charge density wave transition with topological and superconducting properties.

Exotic phenomena due to the interplay of different quantum orders have been observed and the study of these phenomena has emerged as a new frontier in condensed matter research, especially in the two-dimensional limit. Here, we report the coexistence of charge density waves (CDWs), superconductivity, and nontrivial topology in monolayer 1H-MSe (M = Nb, Ta) triggered by momentum-dependent electron-phonon coupling through electron doping. At a critical electron doping concentration, new 2 × 2 CDW phases emerge with nontrivial topology, Dirac cones, and van Hove singularities.

Observation of flat band, Dirac nodal lines and topological surface states in Kagome superconductor CsTiBi.

Kagome lattices of various transition metals are versatile platforms for achieving anomalous Hall effects, unconventional charge-density wave orders and quantum spin liquid phenomena due to the strong correlations, spin-orbit coupling and/or magnetic interactions involved in such a lattice. Here, we use laser-based angle-resolved photoemission spectroscopy in combination with density functional theory calculations to investigate the electronic structure of the newly discovered kagome superconductor CsTiBi, which is isostructural to the AVSb (A = K, Rb or Cs) kagome superconductor family and possesses a two-dimensional kagome network of titanium. We directly observe a striking flat band derived from the local destructive interference of Bloch wave functions within the kagome lattice.

Intertwining of Magnetism and Charge Ordering in Kagome FeGe.

Recent experiments report a charge density wave (CDW) in the antiferromagnet FeGe, but the nature of the charge ordering and the associated structural distortion remains elusive. We discuss the structural and electronic properties of FeGe. Our proposed ground state phase accurately captures atomic topographies acquired by scanning tunneling microscopy.

Strain induced metal-semiconductor transition in two-dimensional topological half metals.

Spintronic applications of two-dimensional (2D) magnetic half metals and semiconductors are thought to be very promising. Here, we suggest a family of stable 2D materials (X = Cl, Br, and I). The monolayer exhibits an in-plane ferromagnetic (FM) ground state with a Curie temperature of 118 K, which is unveiled to be a 2D Weyl half semimetal with two Weyl points of opposite chirality connected by a remarkable Fermi arc.

Topological superconductivity and large spin Hall effect in the kagome family TiX (X = Bi, Sb, Pb, Tl, and In).

Topological superconductors (TSC) become a focus of research due to the accompanying Majorana fermions. However, the reported TSC are extremely rare. Recent experiments reported kagome TSC AVSb (A = K, Rb, and Cs) exhibit unique superconductivity, topological surface states (TSS), and Majorana bound states.

Two-Dimensional Intercalating Multiferroics with Strong Magnetoelectric Coupling.

Intrinsic two-dimensional (2D) multiferroics that couple ferromagnetism and ferroelectricity are rare. Here, we present an approach to achieve 2D multiferroics using powerful intercalation technology. In this approach, metal atoms such as Cu or Ag atoms are intercalated in bilayer CrI to form Cu(CrI) or Ag(CrI).

The -orbital magnetic topological states on a square lattice.

Honeycomb or triangular lattices were extensively studied and thought to be proper platforms for realizing the quantum anomalous Hall effect (QAHE), where magnetism is usually caused by orbitals of transition metals. Here we propose that a square lattice can host three magnetic topological states, including the fully spin-polarized nodal loop semimetal, QAHE and the topologically trivial ferromagnetic semiconductor, in terms of the symmetry and · model analyses that are material independent. A phase diagram is presented.

Epitaxial Growth of Ultraflat Bismuthene with Large Topological Band Inversion Enabled by Substrate-Orbital-Filtering Effect.

Quantum spin Hall (QSH) systems hold promises of low-power-consuming spintronic devices, yet their practical applications are extremely impeded by the small energy gaps. Fabricating QSH materials with large gaps, especially under the guidance of design principles, is essential for both scientific research and practical applications. Here, we demonstrate that large on-site atomic spin-orbit coupling can be directly exploited via the intriguing substrate-orbital-filtering effect to generate large-gap QSH systems and experimentally realized on the epitaxially synthesized ultraflat bismuthene on Ag(111).

Flat Band and Hole-induced Ferromagnetism in a Novel Carbon Monolayer.

In recent experiments, superconductivity and correlated insulating states were observed in twisted bilayer graphene (TBG) with small magic angles, which highlights the importance of the flat bands near Fermi energy. However, the moiré pattern of TBG consists of more than ten thousand carbon atoms that is not easy to handle with conventional methods. By density functional theory calculations, we obtain a flat band at E in a novel carbon monolayer coined as cyclicgraphdiyne with the unit cell of eighteen atoms.

[Manipulative reduction and percutaneous K-wires fixation for treatment of supracondylar fractures of the humerus in children].

Objective: To explore clinical effect of manipulative reduction and percutaneous K-wires fixation in treating supracondylar fractures of the humerus in children.

Methods: From July 2010 to December 2012, clinical data of 52 children with supracondylar fractures of the humerus, which treated with manipulative reduction and percutaneous K-wires fixation, were retrospectively analyzed. Among them, there were 35 males and 17 females with an average age of 6.

[Emergency closed reduction and percutaneous Kirschner wire fixation for treatment of Gartland type II-III supracondylar fractures of the humerus in children].

Objective: To analyze the clinical effect and related risk factors of Gartland type II-III supracondylar fractures of humerus in children in the emergency closed reduction and percutaneous Kirschner wire fixation.

Methods: From January 2008 to June 2013,112 children of Gartland type II to III supracondylar humeral fractures were treated in children in emergency closed reduction and percutaneous K-wire fixation, including 72 males and 40 females with an average age of 6.2 years old ranging from 2 to 11 years old.