Universität zu Köln

Hall, J, Ehlen, N, Berges, J, van Loon, E, van Efferen, C, Murray, C, Rösner, M, Li, J, Senkovskiy, BV, Hell, M, Rolf, M, Heider, T, Asensio, MC, Avila, J, Plucinski, L, Wehling, T, Grüneis, A and Michely, T (2019). Environmental Control of Charge Density Wave Order in Monolayer 2H-TaS2. ACS Nano.

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Abstract

For quasi-freestanding 2H-TaS2 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 3x3 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 TaS2 monolayer possible. As hybridization with substrate bands is absent, the fit yields a precise value for the doping of the TaS2 layer. Additional Li doping shifts the charge density wave to a 2x2 periodicity. Unexpectedly, the bilayer of TaS2 also displays a disordered 2x2 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 TaS2 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

Item Type:	Article
Creators:	Creators Email ORCID ORCID Put Code Hall, J UNSPECIFIED UNSPECIFIED UNSPECIFIED Ehlen, N UNSPECIFIED UNSPECIFIED UNSPECIFIED Berges, J UNSPECIFIED UNSPECIFIED UNSPECIFIED van Loon, E UNSPECIFIED UNSPECIFIED UNSPECIFIED van Efferen, C UNSPECIFIED UNSPECIFIED UNSPECIFIED Murray, C UNSPECIFIED UNSPECIFIED UNSPECIFIED Rösner, M UNSPECIFIED UNSPECIFIED UNSPECIFIED Li, J UNSPECIFIED UNSPECIFIED UNSPECIFIED Senkovskiy, BV UNSPECIFIED UNSPECIFIED UNSPECIFIED Hell, M UNSPECIFIED UNSPECIFIED UNSPECIFIED Rolf, M UNSPECIFIED UNSPECIFIED UNSPECIFIED Heider, T UNSPECIFIED UNSPECIFIED UNSPECIFIED Asensio, MC UNSPECIFIED UNSPECIFIED UNSPECIFIED Avila, J UNSPECIFIED UNSPECIFIED UNSPECIFIED Plucinski, L UNSPECIFIED UNSPECIFIED UNSPECIFIED Wehling, T UNSPECIFIED UNSPECIFIED UNSPECIFIED Grüneis, A UNSPECIFIED UNSPECIFIED UNSPECIFIED Michely, T UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-100194
Identification Number:	10.1021/acsnano.9b03419
Journal or Publication Title:	ACS Nano
Date:	23 August 2019
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Physics > Institute of Physics II
Subjects:	Physics
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/10019