Dresden 2017 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 106: Electronic Structure of Surfaces: Spectroscopy, Surface States III

O 106.6: Vortrag

Freitag, 24. März 2017, 11:45–12:00, WIL C107

spectroscopic imaging STM study on Dirac line node material ZrSiS — •qingyu he — max-planck-institute for solid state research, stuttgart, germany

3D Dirac semi-metals have attracted wide interest in recent condensed matter research. The related Dirac line node materials come into focus due to properties such as unconventional magneto-transport and their potential to host topologically nontrivial phases. The non-symmorphic material ZrSiS is one of the first discovered materials of this new family, hosting a nodal line and an unconventional surface state. [1]

Spectroscopic imaging scanning tunneling microscopy (SI-STM) has been a highly valuable technique to study the electronic structure with high energy resolution. In this presentation, we report the investigation of ZrSiS by SI-STM at the atomic scale, in combination with DFT calculations. Firstly, we succeeded in visualizing the signature of the bulk Dirac line node both in real and momentum space, adding key evidences confirming the nodal line and highlighting its exceptional properties. Secondly, an unconventional surface state related to the breaking of non-symmorphic symmetry was observed and its dispersion relation was mapped. Finally, we also discovered the spectroscopic signatures of a type-II Dirac fermion hosted by the surface state.

Our result has impact beyond ZrSiS, providing crucial insights into the Dirac line node materials and non-symmorphic crystals as well.

[1] Schoop, L. M. et al. Dirac cone protected by non-symmorphic symmetry and three-dimensional Dirac line node in ZrSiS. Nat. Commun. 7:11696