Yongping Du

Unexpected Magnetic Semiconductor Behavior in Zigzag Phosphorene Nanoribbons Driven by Half-Filled One Dimensional Band

Phosphorene, as a novel two-dimensional material, has attracted a great interest due to its novel electronic structure. The pursuit of controlled magnetism in Phosphorene in particular has been persisting goal in this area. In this paper, an antiferromagnetic insulating state has been found in the zigzag phosphorene nanoribbons (ZPNRs) from the comprehensive density functional theory calculations. Comparing with other one-dimensional systems, the magnetism in ZPNRs display several surprising characteristics: (i) the magnetic moments are antiparallel arranged at each zigzag edge; (ii) the magnetism is quite stable in energy (about 29 meV/magnetic-ion) and the band gap is big (about 0.7 eV); (iii) the electronic and magnetic properties is almost independent on the width of nanoribbons; (iv) a moderate compressive strain will induce a magnetic to nonmagnetic as well as semiconductor to metal transition. All of these phenomena arise naturally due to one unique mechanism, namely the electronic instability induced by the half-filled one-dimensional bands which cross the Fermi level at around π/2a. The unusual electronic and magnetic properties in ZPNRs endow them possible potential for the applications in nanoelectronic devices.An antiferromagnetic insulating state has been found in the zigzag phosphorene nanoribbons (ZPNRs) from a comprehensive density functional theory calculations. Comparing with other one-dimensional systems, the magnetism in ZPNRs display several surprising characteristics: (i) the magnetic moments are antiparallel arranged at each zigzag edge; (ii) the magnetism is quite stable in energy (about 29 meV/magnetic-ion) and the band gap is big (about 0.7 eV); (iii) a moderate compressive strain will induce a magnetic to nonmagnetic as well as semiconductor to metal transition. All of these phenomena arise naturally due to one unique mechanism, namely the electronic instability induced by the half-filled one dimensional bands which cross the Fermi level at around {\pi}/2a. The unusual electronic and magnetic properties in ZPNRs endow them great potential for the applications in nanoelectronic devices.

CaTe: a new topological node-line and Dirac semimetal

Combining first-principles calculations and effective model analysis, we predict that CaTe is a topological node-line semimetal in the absence of the spin-orbit coupling. Using a slab model, we obtain the nearly flat drumhead surface state near the Fermi level. When the spin-orbit coupling is included, three node lines will evolve into a pair of Dirac points along the M−R line. These Dirac points are robust and protected by the C4 rotation symmetry. Once this crystal symmetry is broken, the Dirac points will be eliminated, and the system becomes a strong topological insulator.Topological physics: a predicted node-line semimetal CaTeTopological insulators are materials with non-trivial topological order that are insulating in their bulk but conductive on their surface. Recent findings extend the topological states to three-dimensional semimetals that host exotic physical phenomena such as Weyl fermion quantum transport and Hall effects. Among the three types of topological semimetals, three-dimensional Dirac semimetals evolve to Weyl analogs upon breaking of time reversal or inversion symmetry. Here, the theoretical work by a team led by Professor Xiangang Wan from Nanjing University in China proposes a new phase that falls into the third category: node-line semimetals. Based on first-principles calculations and effective model analysis, CsCl structured CaTe is predicted to be a node-line semimetals with characteristic drumhead-like surface states if spin-orbit coupling is absent. When spin-orbit coupling is included, CaTe becomes a three-dimensional Dirac semimetal.

Electronic structure of single-crystalline NdO 0.5 F 0.5 BiS 2 studied by angle-resolved photoemission spectroscopy

NdO

Electronic structure and magnetic properties of NaOsO3

_{0.5}

Dirac and Weyl Semimetal in XYBi (X = Ba, Eu; Y = Cu, Ag and Au).

F

Raman spectra of few-layer phosphorene studied from first-principles calculations

_{0.5}

Microscopic origin of stereochemically active lone pair formation from orbital selective external potential calculations

BiS

Discovery of Intrinsic Ferromagnetic Ferroelectricity in Transition Metal Halides Monolayer

_{2}

Electron-phonon superconductivity in LaO0.5F0.5BiSe2

is a new layered superconductor. We have studied the low-lying electronic structure of a single crystalline NdO

Emergence of topological nodal lines and type-II Weyl nodes in the strong spin-orbit coupling system InNbX2 ( X=S ,Se)

_{0.5}