Perfect Coulomb drag in a dipolar excitonic insulator

• 成果类型: Article
• 署名作者: Nguyen, Phuong X.; Ma, Liguo; Chaturvedi, Raghav; Watanabe, Kenji; Taniguchi, Takashi; Shan, Jie; Mak, Kin Fai
• 署名单位: Cornell University; National Institute for Materials Science; Cornell University
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-13779
• DOI: 10.1126/science.adl1829
• 发表日期: 2025-04-18
• 页码: 274-278
• 关键词: mott transition; condensation; semimetal; contact

摘要

Excitonic insulators (EIs) are a solid-state prototype for bosonic phases of matter that can support charge-neutral exciton currents. However, demonstration of exciton transport in EIs is difficult. In this work, we show that the strong interlayer excitonic correlation at equal electron and hole densities in MoSe2/WSe2 double layers separated by a 2-nanometer barrier yields perfect Coulomb drag under zero magnetic field: A charge current in one layer induces an equal but opposite drag current in the other layer at low temperatures. The drag current ratio remains above 0.9 up to about 20 kelvin. As exciton density increases above the Mott density, the excitons dissociate into an electron-hole plasma abruptly, and only frictional drag is observed. Our experiment may lead to the realization of exciton circuitry and superfluidity.