Department of Physics, University of California at Santa Barbara, Santa Barbara, CA 93106, USA.
School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, AZ 85287, USA.
Science. 2023 May 26;380(6647):860-864. doi: 10.1126/science.add5574. Epub 2023 May 11.
A panoply of unconventional electronic states has been observed in moiré superlattices. Engineering similar bosonic phases remains, however, largely unexplored. We report the observation of a bosonic correlated insulator in tungsten diselenide/tungsten disulfide (WSe/WS) moiré superlattices composed of excitons, that is, tightly bound electron-hole pairs. We develop a pump probe spectroscopy method that we use to observe an exciton incompressible state at exciton filling ν = 1 and charge neutrality, indicating a correlated insulator of excitons. With varying charge density, the bosonic correlated insulator continuously transitions into an electron correlated insulator at charge filling ν = 1, suggesting a mixed correlated insulating state between the two limits. Our studies establish semiconducting moiré superlattices as an intriguing platform for engineering bosonic phases.
在莫尔超晶格中观察到了一系列非常规的电子态。然而，类似玻色子相的工程仍然在很大程度上未被探索。我们报告了在由激子（即紧密束缚的电子-空穴对）组成的二硒化钨/二硫化钨（WSe/WS）莫尔超晶格中观察到玻色关联绝缘相。我们开发了一种泵浦探测光谱学方法，用于观察激子填充 ν = 1 和电中性时的激子不可压缩态，表明激子是关联绝缘体。随着电荷密度的变化，玻色关联绝缘相在电荷填充 ν = 1 时连续过渡到电子关联绝缘相，表明在这两个极限之间存在混合关联绝缘态。我们的研究确立了半导体莫尔超晶格作为工程玻色相的一个有趣平台。
