Group V element analogues of graphene have attracted a lot attention recently due to their semiconducting band structures, which make them promising for next generation electronic and optoelectronic devices based on two-dimensional materials. Theoretical investigations predict high electron mobility, large band gaps, band gap tuning by strain, formation of topological phases, quantum spin Hall effect at room temperature, and superconductivity amongst others. Here, we report a successful formation of freestanding like monolayer arsenene on Ag(111). This was concluded from our experimental atomic and electronic structure data by comparing to results of our theoretical calculations. Arsenene forms a buckled honeycomb layer on Ag(111) with a lattice constant of 3.6 Å showing an indirect band gap of ~1.4 eV as deduced from the position of the Fermi level pinning.The isolation of two-dimensional (2D) carbon in the form of a single layer honeycomb structure (graphene) 1 was the starting point of today's intensive research on various 2D materials. In particular, the electronic properties, i.e., the high conductivity in combination with the linear dispersion of the -band, forming a Dirac cone, are highly interesting for applications in nanoelectronics 2 . However, this utilization of graphene is severely hampered by the lack of an intrinsic band gap, which it shares with graphene like structures of other group IV atoms, i.e., Si, Ge, and Sn 3 .

PurposeEmployee silence is a pervasive workplace phenomenon that can cause severe economic losses to service organizations. Drawing on conservation of resource theory, the present research aims to investigate interpersonal antecedents of employee silence, specifically workplace ostracism while considering the moderating role of negative reciprocity beliefs (NRBs).Design/methodology/approachTwo-wave data collected from 355 employees working in service organizations in Pakistan supported the theorized model. The study used SmartPLS (v 3.2.7) to examine the measurement model and the structural model.FindingsAs projected, the authors found that workplace ostracism was positively related to acquiescence silence and defensive silence, but not related to prosocial silence. Besides, this study’s findings supported two-way interaction involving workplace ostracism and NRB on acquiescence silence and defensive silence, but not on prosocial silence. In particular, the presence of high NRB makes the adverse effects of workplace ostracism even worse.Originality/valueThis study explores the boundary conditions under which employee silence is more likely or less likely to occur. This just makes the current research all the more salient that why and when ostracized employees resort to remain silent in the workplace.

We report a study of the atomic and electronic structures of the ordered Ag 2 Ge surface alloy containing ⅓ monolayer of Ge. Low-energy electron diffraction (LEED), scanning tunneling microscopy (STM), and angle-resolved photoelectron spectroscopy (ARPES) data reveal a symmetry breaking of the expected Ý3 × Ý3 periodicity, which is established for other Ag 2 M alloys (M = Bi, Sb, Pb, and Sn). The deviation from a simple Ý3 × Ý3 structure manifests itself as a splitting of diffraction spots in LEED, as a striped structure with a 6× periodicity including a distortion of the local hexagonal structure in STM, and as a complex surface band structure in ARPES that is quite different from those of the other Ag 2 M alloys. These results are interesting in view of the differences in the atomic and electronic structures exhibited by different group IV elements interacting with Ag(111). Pb and Sn form Ý3 × Ý3 surface alloys on Ag(111), of which Ag 2 Pb shows a surface band structure with a clear spin-orbit split. Si and C form silicene and graphene structures, respectively, with linear band dispersions and the formation of Dirac cones as reported for graphene. The finding that Ag 2 Ge deviates from the ideal (Ý3 × Ý3) Ag 2 Sn and Ag 2 Pb surface alloys makes Ge an interesting "link" between the heavy group IV elements (Sn, Pb) and the light group IV elements (Si, C).

Oxide materials are important candidates for the next generation of electronics due to a wide array of desired properties which they can exhibit alone or when combined with other materials. While SrTiO 3 (STO) is often considered a prototypical oxide, it too hosts a wide array of unusual properties including a two dimensional electron gas (2DEG) which can form at the surface when exposed to UV light. Using layer-by-layer growth of high quality STO films, we show that the 2DEG only forms with the SrO termination and not with the TiO 2 termination, contrary to expectation. This behavior is similarly seen in BaTiO 3 (BTO), in which the 2DEG is only observed for BaO terminated films. These results will allow for a deeper understanding, and better control, of the electronic structure of titanate films, substrates and 1 arXiv:1811.12652v1 [cond-mat.str-el] 30 Nov 2018

Inspired by the unique properties of graphene, research efforts have broadened to investigations of various other two-dimensional materials with the aim of exploring their properties for future applications. Our combined experimental and theoretical study confirms the existence of a binary honeycomb structure formed by Ag and Te on Ag(111). Low-energy electron diffraction shows sharp spots which provide evidence of an undistorted AgTe layer. Band structure data obtained by angle-resolved photoelectron spectroscopy are closely reproduced by first-principles calculations, using density functional theory (DFT). This confirms the formation of a honeycomb structure with one Ag and one Te atom in the unit cell. In addition, the theoretical band structure reproduces also the finer details of the experimental bands, such as a split of one of the AgTe bands.