A type of robust superlattice type-I Weyl semimetal with four Weyl nodes

We investigate the topological properties of the Janus superlattices WTeS and WTeSe by first-principles methods and Wannier-based tight-binding Hamiltonians. The thermal stability of the Janus structures is checked by first-principles molecular dynamics. The topological properties are identified through node chirality, surface states and surface Fermi arcs. Our calculations reveal that both WTeS and WTeSe are Type-I Weyl semimetals with only four Weyl nodes in the Brillouin zone, which is a minimal number in a time reversal symmetry system. This small number of Weyl nodes makes them an excellent platform to study their topological properties experimentally. The Weyl nodes are located in four different quadrants of the Brillouin zone and consequently the separation of Weyl points in reciprocal space, and the length of Fermi arc, is of the order of the magnitude of the reciprocal lattice vector |Gz| as might be easily observed in experiment. The Weyl nodes have approximately the same energy below the Fermi level and are hence accessible by conventional ARPES. In addition, under external strain, the Weyl semimetal state is more robust than the sister compounds Td-WTe2/MoTe2. Our findings are important to explore Weyl fermion physics and useful for realizing possible applications of Weyl semimetal materials in future topological electronic devices

Application of numerical inverse method in calculation of composition-dependent interdiffusion coefficients in finite diffusion couples

The previously developed numerical inverse method was applied to determine the composition-dependent interdiffusion coefficients in single-phase finite diffusion couples. The numerical inverse method was first validated in a fictitious binary finite diffusion couple by pre-assuming four standard sets of interdiffusion coefficients. After that, the numerical inverse method was then adopted in a ternary Al-Cu-Ni finite diffusion couple. Based on the measured composition profiles, the ternary interdiffusion coefficients along the entire diffusion path of the target ternary diffusion couple were obtained by using the numerical inverse approach. The comprehensive comparisons between the computations and the experiments indicate that the numerical inverse method is also applicable to high-throughput determination of the composition-dependent interdiffusion coefficients in finite diffusion couples

PlantQTL-GE: a database system for identifying candidate genes in rice and Arabidopsis by gene expression and QTL information

We have designed and implemented a web-based database system, called PlantQTL-GE, to facilitate quantitatine traits locus (QTL) based candidate gene identification and gene function analysis. We collected a large number of genes, gene expression information in microarray data and expressed sequence tags (ESTs) and genetic markers from multiple sources of Oryza sativa and Arabidopsis thaliana. The system integrates these diverse data sources and has a uniform web interface for easy access. It supports QTL queries specifying QTL marker intervals or genomic loci, and displays, on rice or Arabidopsis genome, known genes, microarray data, ESTs and candidate genes and similar putative genes in the other plant. Candidate genes in QTL intervals are further annotated based on matching ESTs, microarray gene expression data and cis-elements in regulatory sequences. The system is freely available at