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HL: Fachverband Halbleiterphysik
HL 13: 2D Materials III – Interlayer excitons
HL 13.5: Vortrag
Montag, 9. März 2026, 17:45–18:00, POT/0081
Influence of hBN spacer layers on atomic reconstruction in MoSe2/WSe2 heterostructures probed by electron microscopy — •Johannes Figueiredo1,2, Kaiyuan Chen3, Aubrey Penn4, Mirco Troue1,2, Sebastian Loy1,2, Frances M. Ross3, Julian Klein3, and Alexander Holleitner1,2 — 1Walter Schottky Institute, TU Munich — 2MCQST — 3Massachusetts Institute of Technology — 4MIT.nano
Atomically thin hexagonal boron nitride (hBN) tunnelling barriers in transition metal dichalcogenide (TMD) heterobilayers have recently facilitated the observation of macroscopic interlayer exciton phases interpreted as possible condensation and superfluid phenomena. However, such hBN spacer layers are also expected to modify moiré-driven atomic reconstruction. Here, we resolve local stacking configurations, lattice relaxation patterns and twist-angle variations across encapsulated MoSe2/WSe2 heterobilayers using a combination of high-angle annular dark-field scanning transmission electron microscopy (HAADF STEM), convergent-beam electron diffraction and four-dimensional STEM. Our analysis shows that the presence and thickness of the hBN spacer layers alter the balance between elastic relaxation and interlayer registry, producing a reconstruction landscape that differs qualitatively from that of directly contacted MoSe2/WSe2 bilayers. We also discuss how the resulting changes in structural homogeneity tune the moiré potential experienced by interlayer excitons and outline the implications for realizing spatially uniform macroscopic exciton phases in TMD-based quantum devices.
Keywords: Interlayer Excitons; Atomic Reconstruction; Electron Microscopy