Perfect Coulomb drag and exciton transport in an excitonic insulator

• 成果类型: Article
• 署名作者: Qi, Ruishi; Joe, Andrew Y.; Zhang, Zuocheng; Xie, Jingxu; Feng, Qixin; Lu, Zheyu; Wang, Ziyu; Taniguchi, Takashi; Watanabe, Kenji; Tongay, Sefaattin; Wang, Feng
• 署名单位: University of California System; University of California Berkeley; United States Department of Energy (DOE); Lawrence Berkeley National Laboratory; University of California System; University of California Berkeley; Xi'an Jiaotong University; National Institute for Materials Science; National Institute for Materials Science; Arizona State University; Arizona State University-Tempe; University of California System; University of California Berkeley
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-10335
• DOI: 10.1126/science.adl1839
• 发表日期: 2025-04-18
• 关键词: wigner crystal; condensation

摘要

Strongly coupled electron-hole bilayers can host quantum states of interlayer excitons, such as high-temperature exciton condensates at zero magnetic field. This state is predicted to feature perfect Coulomb drag, where a current in one layer is accompanied by an equal but opposite current in the other. We used an optical technique to probe the electrical transport of correlated electron-hole bilayers based on MoSe2/hBN/WSe2 heterostructures. We observed perfect Coulomb drag in the excitonic insulator phase at low temperatures; the counterflow resistance of interlayer excitons remained finite. These results indicate the formation of an exciton gas that does not condense into a superfluid. Our work demonstrates that dynamic optical spectroscopy provides a powerful tool for probing exciton transport behavior in correlated electron-hole fluids.