Dresden 2026 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 12: Focus Session: Tunable Correlations in van der Waals Quantum Materials I (joint session TT/DS/HL)
TT 12.3: Topical Talk
Monday, March 9, 2026, 16:00–16:30, HSZ/0003
Optical signatures of interlayer electron coherence in a bilayer semiconductor — •Nadine Leisgang1,2, Xiaoling Liu2, Pavel Dolgirev2, Philip Kim2, and Mikhail Lukin2 — 1Phillips-Universität Marburg, Germany — 2Harvard University, United States
Emergent strongly correlated electronic phenomena in atomically thin transition-metal dichalcogenides represent an exciting frontier in condensed matter physics, with examples ranging from bilayer superconductivity and electronic Wigner crystals to the ongoing search for exciton condensation. Here, we take a step towards the latter by reporting experimental signatures of unconventional coupling of interlayer excitons consistent with coherence between interlayer electrons in a transition-metal dichalcogenide bilayer. We investigate naturally-grown MoS2 homobilayers integrated in a dual-gate device structure allowing independent control of the electron density and out-of-plane electric field. When the bilayer is electron-doped under conditions where tunnelling between layers is negligible, we observe that two interlayer excitons - which normally should not interact - hybridize in a way distinct from both conventional level crossing and anti-crossing. We show that these observations can be explained by quasi-static random coupling between the excitons, which increases with electron density and decreases with temperature. We argue that this phenomenon is indicative of a spatially fluctuating order parameter in the form of interlayer electron coherence - a theoretically predicted many-body state that has yet to be unambiguously established experimentally outside the quantum Hall regime.
Keywords: condensed matter physics; two-dimensional materials; interlayer excitons; strongly correlated electrons