Realization of a Type-II Nodal-Line Semimetal in MgBi.

Nodal-line semimetals (NLSs) represent a new type of topological semimetallic phase beyond Weyl and Dirac semimetals in the sense that they host closed loops or open curves of band degeneracies in the Brillouin zone. Parallel to the classification of type-I and type-II Weyl semimetals, there are two types of NLSs. The type-I NLS phase has been proposed and realized in many compounds, whereas the exotic type-II NLS phase that strongly violates Lorentz symmetry has remained elusive.

Correction: Origin of the temperature dependence of the energy gap in Cr-doped BiSe.

Correction for 'Origin of the temperature dependence of the energy gap in Cr-doped Bi2Se3' by Turgut Yilmaz et al., Phys. Chem.

Origin of the temperature dependence of the energy gap in Cr-doped BiSe.

Recent progress in impurity-doped topological insulators has shown that the gap at the Dirac point shrinks with reducing temperature. This is an obstacle for experimental realization of the quantum anomalous Hall effect at higher temperature due to the requirement of a larger energy gap. In order to solve this puzzle, we study the gap at the Dirac point by performing temperature-dependent photoemission spectroscopy and X-ray diffraction experiments in Cr-doped Bi2Se3.