SKM 2023 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 1: 2D Materials I (joint session HL/CPP)

HL 1.5: Vortrag

Montag, 27. März 2023, 10:45–11:00, POT 81

Electronic effects of non-uniformly strained 2D TMDCs — •Mohammadreza Daqiqshirazi and Thomas Brumme — Chair of Theoretical Chemistry, Technische Universität Dresden, Bergstraße 66c, 01069 Dresden, Germany

Strain plays an important role in most 2D materials since there is a strong influence of the strain state on the relative band alignment of different valleys in the electronic band structure. The effects of non-uniform strain on the properties of 2D materials are scarcely studied theoretically, even if in experiments a lot of different structures can be found in which a spatial varying strain state is present such as wrinkles or folds. Here, we are investigating how such non-uniform strain influences the electronic properties of the prototypical 2D materials WSe2 and MoS2.We study nanoscale wrinkles and nanotubes in detail and discuss important differences in the strain distribution and magnitude, also to understand if nanotubes could be used as a model system for non-uniformly strained systems. Using Density Functional Theory we find that the inclusion of spin-orbit interaction is crucial to correctly predict the changes in the band structure of wrinkled 2D materials as the non-uniform strain changes the symmetry compared to a flat layer. This introduces a strong Rashba-like splitting of the valence-band maximum near the Γ point. The situation complicates even more with the addition of an extra layer forming a bilayer or a hetrobilayer. The spatial varying band alignments in wrinkled multilayers can lead to new interlayer excitons which are confined to certain regions of the system.