Surface floating 2D bands in layered nonsymmorphic semimetals: ZrSiS and related compounds

Andreas Topp, Raquel Queiroz, Andreas Grüneis, Lukas Müchler, Andreas W. Rost, Andrei Varykhalov, Dmitry Marchenko, Maxim Krivenkov, Fanny Rodolakis, Jessica L. McChesney, Bettina V. Lotsch, Leslie M. Schoop, Christian R. Ast

Research output: Contribution to journalArticlepeer-review

Abstract

In this work, we present a model of the surface states of nonsymmorphic semimetals. These are derived from surface mass terms that lift the high degeneracy imposed on the band structure by the nonsymmorphic bulk symmetries. Reflecting the reduced symmetry at the surface, the bulk bands are strongly modified. This leads to the creation of two-dimensional floating or unpinned bands, which are distinct from Shockley states, quantum well states, or topologically protected surface states. We focus on the layered semimetal ZrSiS to clarify the origin of its surface states. We demonstrate an excellent agreement between density functional theory calculations and angle-resolved photoemission spectroscopy measurements and present an effective four-band model in which similar surface bands appear. Finally, we emphasize the role of the surface chemical potential by comparing the surface density of states in samples with and without potassium coating. Our findings can be extended to related compounds and generalized to other crystals with nonsymmorphic symmetries.
Original languageEnglish
Article number041073
Number of pages9
JournalPhysical Review X
Volume7
Issue number4
DOIs
Publication statusPublished - 28 Dec 2017

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