Interlayer Fermi Polarons in Bilayer MoTe$_2$

Year: 2026

Type: preprint

Abstract: Atomic bilayers of transition metal dichalcogenides (TMDs) host quantum phases governed by the layer degree of freedom, including bilayer Wigner crystals, fractional Chern insulators, and exciton condensates. These phases are probed primarily through exciton spectroscopy, yet it remains poorly understood how excitons and carriers interact to form Fermi polarons in bilayers, where both the impurity and the Fermi sea carry a layer pseudospin. Progress has been limited because most TMD bilayers have momentum-indirect optical bandgaps, in which non-radiative decay and inhomogeneous broadening obscure the intrinsic spectra. Here, we show that bilayer MoTe$_2$, unlike most TMD bilayers, retains a direct optical bandgap, providing a clean platform for studying bilayer Fermi-polaron physics. In a dual-gated device, an out-of-plane electric field continuously tunes the hybridization between intralayer and interlayer excitons, forming layer-coherent excitons. Upon electrostatic doping, the excitonic spectrum evolves into multiple polaron branches, controlled by both carrier doping and the out-of-plane electric field. Among these, we identify a polaron with no analog in monolayers, in which a layer-coherent exciton is dressed by carriers in the opposite layer, and is quantitatively captured by our field-theoretic model. Our results establish that pseudospin structure in both the impurity and the bath reshapes polaron formation, opening new avenues to many-body states such as Bose-Einstein condensates with interlayer coherence.

Source: arXiv (Cornell University)

DOI: 10.48550/arxiv.2609.38045

Authors: Ni, Ruihao, Dizer, Eugen, Wolf, Maximilian, Le, Son T., Jois, Sharadh, Schwartz, Jeffrey J., Gu, Liuxin, Ma, Rundong, Park, Suji, Gao, Beini, Zhang, Lifu, Jang, Houk, Taniguchi, Takashi, Watanabe, Kenji, Hanbicki, Aubrey T., Friedman, Adam L., Schmidt, Richard, Zhou, You

Institutions: University of Maryland, College Park, Heidelberg University, Brookhaven National Laboratory, Center for Functional Nanomaterials, National Institute for Materials Science, Research Center for Materials Nanoarchitectonics, Maryland Quantum Materials Center

Language: English

Topic: 2D Materials and Applications

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

Open Access status: green

Funders: National Science Foundation, U.S. Department of Energy, Deutsche Forschungsgemeinschaft, Ministry of Education, Culture, Sports, Science and Technology, Office of Science, Division of Materials Research, Basic Energy Sciences, Core Research for Evolutional Science and Technology, Army Research Office, Brookhaven National Laboratory

OpenAlex ID: W7214959967