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The $C_{2v}$ symmetry of the W(110) surface influences strongly the spin-polarized Dirac-cone-like surface state within a spin-orbit-induced symmetry gap. We present a detailed angle-resolved photoemission study with $s$- and $p$-polarized light along three different symmetry lines. The Dirac-cone-like feature appears along $bar{Gamma}bar{H}$ and $bar{Gamma}bar{S}$, while it is strongly deformed along $bar{Gamma}bar{N}$. A two-fold $Sigma_{3}$ symmetry of the $d$-type surface state is identified from photoemission experiments using linear polarized light. Our results are well described by model calculations based on an effective Hamiltonian with $C_{2v}$ symmetry including Rashba parameters up to third order. The flattened Dirac cone of the surface state is caused by hybridization with bulk continuum states of $Sigma_{1}$ and $Sigma_{2}$ symmetry. The spin texture of this state obtained from the model calculations shows a quasi-one dimensional behavior. This finding opens a new avenue in the study of $d$-electron-based persistent spin helix systems and/or weak topological insulators.
The surface of W(110) exhibits a Dirac-cone-like surface state with $d$ character within a spin-orbit-induced symmetry gap. As a function of wave vector parallel to the surface, it shows nearly massless energy dispersion and a pronounced spin polariz
Realizing stable two-dimensional (2D) Dirac points against spin-orbit coupling (SOC) has attracted much attention because it provides a platform to study the unique transport properties. In previous work, Young and Kane [Phys. Rev. Lett. textbf{115},
Massless Dirac electrons in condensed matter have attracted considerable attention. Unlike conventional electrons, Dirac electrons are described in the form of two-component wave functions. In the surface state of topological insulators, these two co
This paper presents a theoretical analysis on bulk and edge states in honeycomb lattice photonic crystals with and without time-reversal and/or space-inversion symmetries. Multiple Dirac cones are found in the photonic band structure and the mass gap
The unoccupied states in topological insulators Bi_2Se_3, PbSb_2Te_4, and Pb_2Bi_2Te_2S_3 are studied by the density functional theory methods. It is shown that a surface state with linear dispersion emerges in the inverted conduction band energy gap