近日，美国加州大学伯克利分校Feng Wang团队研究了激子绝缘体中的完美库仑阻力和激子输运。该研究于2025年4月18日发表在《科学》杂志上。
强耦合的电子-空穴双层可以容纳层间激子的量子态，例如零磁场下的高温激子凝聚体。这种状态被预测为具有完美的库仑阻力，其中一层中的电流伴随着另一层中相等但相反的电流。研究组使用光学技术探测了基于MoSe2/hBN/WSe2异质结构的相关电子-空穴双层的电输运。
他们观察到低温下激子绝缘体相中的完美库仑阻力；层间激子的逆流电阻仍然有限。这些结果表明，激子气体的形成不会凝结成超流体。该工作表明，动态光谱学为探测相关电子-空穴流体中的激子输运行为提供了强有力的工具。
附：英文原文
Title: Perfect Coulomb drag and exciton transport in an excitonic insulator
Author: Ruishi Qi, Andrew Y. Joe, Zuocheng Zhang, Jingxu Xie, Qixin Feng, Zheyu Lu, Ziyu Wang, Takashi Taniguchi, Kenji Watanabe, Sefaattin Tongay, Feng Wang
Issue&Volume: 2025-04-18
Abstract: 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.
DOI: adl1839
Source: https://www.science.org/doi/10.1126/science.adl1839