Environmental Control of Charge Density Wave Order in Monolayer 2H-TaS 2 .

Autor: Hall J; II. Physikalisches Institut , Universität zu Köln , Zülpicher Straße 77 , 50937 Köln , Germany., Ehlen N; II. Physikalisches Institut , Universität zu Köln , Zülpicher Straße 77 , 50937 Köln , Germany., Berges J; Institut für Theoretische Physik, Bremen Center for Computational Materials Science , Universität Bremen , Otto-Hahn-Allee 1 , 28359 Bremen , Germany., van Loon E; Institut für Theoretische Physik, Bremen Center for Computational Materials Science , Universität Bremen , Otto-Hahn-Allee 1 , 28359 Bremen , Germany., van Efferen C; II. Physikalisches Institut , Universität zu Köln , Zülpicher Straße 77 , 50937 Köln , Germany., Murray C; II. Physikalisches Institut , Universität zu Köln , Zülpicher Straße 77 , 50937 Köln , Germany., Rösner M; Institute for Molecules and Materials , Radboud University , 6525 AJ Nijmegen , The Netherlands., Li J; II. Physikalisches Institut , Universität zu Köln , Zülpicher Straße 77 , 50937 Köln , Germany., Senkovskiy BV; II. Physikalisches Institut , Universität zu Köln , Zülpicher Straße 77 , 50937 Köln , Germany., Hell M; II. Physikalisches Institut , Universität zu Köln , Zülpicher Straße 77 , 50937 Köln , Germany., Rolf M; II. Physikalisches Institut , Universität zu Köln , Zülpicher Straße 77 , 50937 Köln , Germany., Heider T; Peter Grünberg Institut (PGI-6) , Forschungszentrum Jülich GmbH , 52425 Jülich , Germany., Asensio MC; ANTARES Beamline , Synchrotron SOLEIL and Universite Paris-Saclay , L' Orme des Merisiers, Saint Aubin-BP 48 , 91192 Gif sur Yvette Cedex , France., Avila J; ANTARES Beamline , Synchrotron SOLEIL and Universite Paris-Saclay , L' Orme des Merisiers, Saint Aubin-BP 48 , 91192 Gif sur Yvette Cedex , France., Plucinski L; Peter Grünberg Institut (PGI-6) , Forschungszentrum Jülich GmbH , 52425 Jülich , Germany., Wehling T; Institut für Theoretische Physik, Bremen Center for Computational Materials Science , Universität Bremen , Otto-Hahn-Allee 1 , 28359 Bremen , Germany., Grüneis A; II. Physikalisches Institut , Universität zu Köln , Zülpicher Straße 77 , 50937 Köln , Germany., Michely T; II. Physikalisches Institut , Universität zu Köln , Zülpicher Straße 77 , 50937 Köln , Germany.
Jazyk: angličtina
Zdroj: ACS nano [ACS Nano] 2019 Sep 24; Vol. 13 (9), pp. 10210-10220. Date of Electronic Publication: 2019 Aug 30.
DOI: 10.1021/acsnano.9b03419
Abstrakt: For quasi-freestanding 2H-TaS 2 in monolayer thickness grown by in situ molecular beam epitaxy on graphene on Ir(111), we find unambiguous evidence for a charge density wave close to a 3 × 3 periodicity. Using scanning tunneling spectroscopy, we determine the magnitude of the partial charge density wave gap. Angle-resolved photoemission spectroscopy, complemented by scanning tunneling spectroscopy for the unoccupied states, makes a tight-binding fit for the band structure of the TaS 2 monolayer possible. As hybridization with substrate bands is absent, the fit yields a precise value for the doping of the TaS 2 layer. Additional Li doping shifts the charge density wave to a 2 × 2 periodicity. Unexpectedly, the bilayer of TaS 2 also displays a disordered 2 × 2 charge density wave. Calculations of the phonon dispersions based on a combination of density-functional theory, density-functional perturbation theory, and many-body perturbation theory enable us to provide phase diagrams for the TaS 2 charge density wave as functions of doping, hybridization, and interlayer potentials, and offer insight into how they affect lattice dynamics and stability. Our theoretical considerations are consistent with the experimental work presented and shed light on previous experimental and theoretical investigations of related systems.
Databáze: MEDLINE
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