Regensburg 2025 – scientific programme
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O: Fachverband Oberflächenphysik
O 36: Poster 2D Materials: Electronic Structure and Exitations (joint session O/HL)
O 36.5: Poster
Tuesday, March 18, 2025, 13:30–15:30, P3
Polarons in single-layer MoS2 via downfolding approach to the coupling of electronic and nuclear degrees of freedom — •Laura Pätzold1, Camiel van Efferen2, Arne Schobert1, Tfyeche Y. Tounsi2, Michael Winter1, Mark Georger2, Affan Safeer2, Christian Krämer2, Jeison Fischer2, Jan Berges3, Thomas Michely2, Roberto Mozara1, Wouter Jolie2, and Tim O. Wehling1,4 — 1U Hamburg — 2U Köln — 3U Bremen — 4The Hamburg Centre for Ultrafast Imaging
A polaron is a quasiparticle describing a localized bound state resulting from the interaction of charge carriers with lattice vibrations. Though they are a well-studied phenomenon, experimental observations of polarons in 2D crystals are sparse. Here, we present the theoretical analysis of polaronic distortions in n-doped single-layer MoS2 via a downfolding approach with linear electron-lattice coupling based on density functional theory calculations [1]. With this, a multi-polaronic distortion, caused by a renormalized M-point phonon, can be stabilized on supercells of up to 18×18. We compare our results to scanning tunneling microscopy measuremens obtained on n-doped single-layer MoS2, which support the existence of polarons emerging from the coupling of non-polar zone-boundary phonons to Bloch electrons. This tunneling into the vibrationally coupled polaronic states is visible through evenly spaced peaks around the Fermi energy in the differential conductance, whose spacing matches the frequency of the M-point phonon responsible for the multi-polaronic distortion in our simulations.
[1] A. Schobert et al., SciPost Phys. 16, 046 (2024)
Keywords: MoS2; Polarons; Downfolding