Ambipolar metal-insulator transition in bilayer MoSe2
Abstract
When Coulomb interactions dominate kinetic energy, dilute two-dimensional carriers form a Wigner solid. Both its melting and disorder-driven localization can drive density-tuned metal-insulator transitions, but their relative roles and interplay have been debated for decades. Atomically thin semiconductors offer a new test because transport and scanning tunneling microscopy can probe the same material, yet poor contacts impede transport where correlations are strongest. Here we introduce contact-free radio-frequency reflectometry that senses sheet resistance through capacitive gate coupling. It resolves the electron and previously inaccessible hole transitions in the same bilayer MoSe2 device, whose carriers share disorder but not mass. Their critical densities differ fourfold yet correspond to comparable Coulomb-to-kinetic-energy ratios, where tunneling microscopy finds solid-liquid coexistence. Magnetoresistance peaks sharply at each transition, reflecting a Pomeranchuk-like, field-driven expansion of the Wigner solid against the correlated liquid. Our results demonstrate interaction-driven transitions in high-quality two-dimensional semiconductors, opening quantitative transport in contact-limited systems.
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BibTeX
@misc{kim2026ambipolar,
title = {{Ambipolar metal-insulator transition in bilayer MoSe2}},
author = {Ha-Leem Kim and Hyungbin Lim and Terry Wu and Amogh Y. Waghmare and Garima Gupta and Takashi Taniguchi and Kenji Watanabe and Archana Raja and Eric Y. Ma and Feng Wang},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.09036},
eprint = {2610.09036},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.09036},
}
RIS
TY - UNPB
TI - Ambipolar metal-insulator transition in bilayer MoSe2
AU - Ha-Leem Kim
AU - Hyungbin Lim
AU - Terry Wu
AU - Amogh Y. Waghmare
AU - Garima Gupta
AU - Takashi Taniguchi
AU - Kenji Watanabe
AU - Archana Raja
AU - Eric Y. Ma
AU - Feng Wang
PY - 2026
DA - 2026/10/06
PB - arXiv
DO - 10.48550/arxiv.2610.09036
UR - https://arxiv.org/abs/2610.09036
AB - When Coulomb interactions dominate kinetic energy, dilute two-dimensional carriers form a Wigner solid. Both its melting and disorder-driven localization can drive density-tuned metal-insulator transitions, but their relative roles and interplay have been debated for decades. Atomically thin semiconductors offer a new test because transport and scanning tunneling microscopy can probe the same material, yet poor contacts impede transport where correlations are strongest. Here we introduce contact-free radio-frequency reflectometry that senses sheet resistance through capacitive gate coupling. It resolves the electron and previously inaccessible hole transitions in the same bilayer MoSe2 device, whose carriers share disorder but not mass. Their critical densities differ fourfold yet correspond to comparable Coulomb-to-kinetic-energy ratios, where tunneling microscopy finds solid-liquid coexistence. Magnetoresistance peaks sharply at each transition, reflecting a Pomeranchuk-like, field-driven expansion of the Wigner solid against the correlated liquid. Our results demonstrate interaction-driven transitions in high-quality two-dimensional semiconductors, opening quantitative transport in contact-limited systems.
ER -