Band splitting and Weyl nodes in trigonal tellurium studied by angle-resolved photoemission spectroscopy and density functional theory

We have performed high-resolution angle-resolved photoemission spectroscopy (ARPES) on trigonal tellurium consisting of helical chains in the crystal. Through the band-structure mapping in the three-dimensional Brillouin zone, we found a definitive evidence for the band splitting originating from the chiral nature of crystal. A direct comparison of the band dispersion between the ARPES results and the first-principles band-structure calculations suggests the presence of Weyl nodes and tiny spin-polarized hole pockets around the H point. The present result opens a pathway toward studying the interplay among crystal symmetry, band structure, and exotic physical properties in chiral crystals.Comment: 6 pages, 3 figure

<Articles><Geomorphology>Weathering rind characteristics of blocky deposits in a deglaciated cirque on Mt.Yakushi,the Northern Japanese Alps

Weathering-rind thickness(WRT) has been used as an indicator of relative ages of giacial and periglacial deposits in high mountain areas (e.g. Birkeland,1973; Koizumi and Aoyagi,1993;Aoki,2000). The method is simple and useful but may include errors arising from ..

Theoretical Analysis of the Reduction of Neel Temperature in La2_{2}(Cu1−x_{1-x}Zn(or Mg)x)_x)O4_{4}

Using Tyablikov's decoupling approximation, we calculate the initial suppression rate of the Neel temperature, $R_{IS}=-lim_{x-> 0} T^{-1}_{N} dT_{N}/dx$, in a quasi two-dimensional diluted Heisenberg antiferromagnet with nonmagnetic impurities of concentration $x$. In order to explain an experimental fact that $R^{(Zn)}_{IS}=3.4$ of the Zn-substitution is different from $R^{(Mg)}_{IS}=3.0$ of the Mg-substitution, we propose a model in which impurity substitution reduces the intra-plane exchange couplings surrounding impurities, as well as dilution of spin systems. The decrease of 12% in exchange coupling constants by Zn substitution and decrease of 6% by Mg substitution explain those two experimental results, when an appropriate value of the interplane coupling is used.Comment: 2 pages, 3 figure

Density Matrix Renormalization Group Study of the Disorder Line in the Quantum ANNNI Model

We apply Density Matrix Renormalization Group methods to study the phase diagram of the quantum ANNNI model in the region of low frustration where the ferromagnetic coupling is larger than the next-nearest-neighbor antiferromagnetic one. By Finite Size Scaling on lattices with up to 80 sites we locate precisely the transition line from the ferromagnetic phase to a paramagnetic phase without spatial modulation. We then measure and analyze the spin-spin correlation function in order to determine the disorder transition line where a modulation appears. We give strong numerical support to the conjecture that the Peschel-Emery one-dimensional line actually coincides with the disorder line. We also show that the critical exponent governing the vanishing of the modulation parameter at the disorder transition is $\beta_q = 1/2$.Comment: 4 pages, 5 eps figure

Consumer expectations of product lifetimes around the world: a review of global research findings and methods

This paper presents the findings of research to identify and evaluate current studies into consumer expectations of product lifetimes across durable goods. Following a literature review, studies were classified using a product categorisation scheme formulated at Nottingham Trent University and a product lifetime expectations typology adapted from Oguchi et al. (2016a) was developed. The results would appear to suggest that consumer expectations of product lifetimes are in decline, and that those in the United Kingdom appear to be lower than those in other parts of the world. However, identifying differences in consumer expectations of product lifetimes is hindered by the different methods employed in studies, as face-to-face interviews, and online, telephone and postal studies all have the potential to produce different results. Three key challenges to furthering research into consumer expectations of product lifetimes were identified: Product coverage, definitions of consumer expectations and sampling strategies. Only if these challenges can be addressed will researchers be able to draw meaningful conclusions on both personal and cultural trends in expected product lifetimes and make a positive contribution to addressing both material and social aspects of the circular economy

A-site driven ferroelectricity in strained ferromagnetic L2NiMnO6 thin films

We report on theoretical and experimental investigation of A-site driven ferroelectricity in ferromagnetic La2NiMnO6 thin films grown on SrTiO3 substrates. Structural analysis and density functional theory calculations show that epitaxial strain stretches the rhombohedral La2NiMnO6 crystal lattice along the [111]cubic direction, triggering a displacement of the A-site La ions in the double perovskite lattice. The lattice distortion and the A-site displacements stabilize a ferroelectric polar state in ferromagnetic La2NiMnO6 crystals. The ferroelectric state only appears in the rhombohedral La2NiMnO6 phase, where MnO6 and NiO6 octahedral tilting is inhibited by the 3-fold crystal symmetry. Electron localization mapping showed that covalent bonding with oxygen and 6s orbital lone pair formation are negligible in this material.Comment: in pres

Microscopic Evidence for Evolution of Superconductivity by Effective Carrier Doping in Boron-doped Diamond:11B-NMR study

We have investigated the superconductivity discovered in boron (B)-doped diamonds by means of 11B-NMR on heteroepitaxially grown (111) and (100) films. 11B-NMR spectra for all of the films are identified to arise from the substitutional B(1) site as single occupation and lower symmetric B(2) site substituted as boron+hydrogen(B+H) complex, respectively. A clear evidence is presented that the effective carriers introduced by B(1) substitution are responsible for the superconductivity, whereas the charge neutral B(2) sites does not offer the carriers effectively. The result is also corroborated by the density of states deduced by 1/T1T measurement, indicating that the evolution of superconductivity is driven by the effective carrier introduced by substitution at B(1) site.Comment: 4 pages, 6 figures, to be published in Phys. Rev. B (Brief report