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.
View Article and Find Full Text PDFObjective: To explore the impact of levothyroxine (L-T4) administration at different time points on pregnancy outcomes and offspring development in patients with subclinical hypothyroidism (SCH).
Methods: In this retrospective study, medical records of 107 patients with SCH treated in Huzhou Nanxun District People's Hospital from February 2021 to March 2023 were retrospectively reviewed. Of them, 55 patients received treatment before eight gestational weeks (Early group), and 52 patients received treatment after eight gestational weeks (Mid group).
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.
View Article and Find Full Text PDFObjective: To explore clinical effect of closed reduction percutaneous elastic intramedullary nail assisted by arthrography in the treatment of radial neck fracture in children.
Methods: A retrospective analysis was performed on 23 children with radial neck fracture treated with arthrography assisted closed reduction and percutaneous elastic intramedullary nail internal fixation (arthrography with elastic nail group) from January 2019 to December 2022, including 12 males and 11 females, aged from 2 to 12 years old with an average of (7.36±1.
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).
View Article and Find Full Text PDFNon-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.
View Article and Find Full Text PDFThe 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.
View Article and Find Full Text PDFResearch (Wash D C)
October 2023
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.
View Article and Find Full Text PDFExotic 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.
View Article and Find Full Text PDFKagome 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.
View Article and Find Full Text PDFRecent 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.
View Article and Find Full Text PDFSpintronic 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.
View Article and Find Full Text PDFTopological 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.
View Article and Find Full Text PDFJ Phys Chem Lett
December 2022
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).
View Article and Find Full Text PDFThe kagome lattice has attracted intense interest with the promise of realizing topological phases built from strongly interacting electrons. However, fabricating two-dimensional (2D) kagome materials with nontrivial topology is still a key challenge. Here, we report the growth of single-layer iron germanide kagome nanoflakes by molecular beam epitaxy.
View Article and Find Full Text PDFHoneycomb 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.
View Article and Find Full Text PDFObjective: To compare the effect of Direct Anterior Approach (DAA) and Orthopadisehe Chirurgie Munchen (OCM) in the prone position on early joint function after primary hip arthroplasty in young adults.
Methods: In this retrospective analysis, 85 patients who received primary hip arthroplasty between September 2018 and January 2020 were enrolled and divided into the OCM group (43 cases with OCM) and the DAA group (42 cases with DAA) according to the different surgical methods. The general operative conditions, postoperative conditions and imaging manifestations, postoperative pain, changes in WOMAC scale scores, and the occurrence of adverse reactions were compared between the two groups.
In a two-dimensional (2D) Kagome lattice, the ideal Kagome bands including Dirac cones, van Hove singularities, and a flat band are highly expected, because they can provide a promising platform to investigate novel physical phenomena. However, in the reported Kagome materials, the complex 3D and multiorder electron hoppings result in the disappearance of the ideal Kagome bands in these systems. Here, we propose an alternative way to achieve the ideal Kagome bands in non-Kagome materials by confining excess electrons in the system to the crystal interstitial sites to form a 2D Kagome lattice, coined as a Kagome electride.
View Article and Find Full Text PDFQuantum 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).
View Article and Find Full Text PDFIn 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.
View Article and Find Full Text PDFObjective: To assess the clinical effectiveness and safety of anterior versus posterior approach for multilevel cervical spondylotic myelopathy.
Methods: The following databases were searched: the Cochrane Library, PubMed, EM base, OVID, CBM, Wanfang Data, CNKI. Relevant journals were manually searched for randomized controlled trials or clinical controlled trials(CCTs) that investigated the clinical effectiveness and safety of anterior and posterior approach for multilevel cervical spondylotic myelopathy.