1Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China 2School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China 3Songshan Lake Materials Laboratory, Dongguan 523808, China 4College of Physics and Electronic Engineering, Center for Computational Sciences, Sichuan Normal University, Chengdu 610068, China 5Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan 6International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
Abstract：Moiré superlattices have emerged as a highly controllable quantum platform for exploration of various fascinating phenomena, such as Mott insulator states, ferroelectric order, unconventional superconductivity and orbital ferromagnetism. Although remarkable progress has been achieved, current research in moiré physics has mainly focused on the single species properties, while the coupling between distinct moiré quantum phenomena remains elusive. Here we demonstrate, for the first time, the strong coupling between ferroelectricity and correlated states in a twisted quadrilayer MoS$_{2}$ moiré superlattice, where the twist angles are controlled in sequence to be $\sim$ $57^{\circ}$, $\sim$ $0^{\circ}$, and $\sim$ $-57 ^{\circ}$. Correlated insulator states are unambiguously established at moiré band filling factors $v = 1$, 2, 3 of twisted quadrilayer MoS$_{2}$. Remarkably, ferroelectric order can occur at correlated insulator states and disappears quickly as the moiré band filling deviates from the integer fillings, providing smoking gun evidences of the coupling between ferroelectricity and correlated states. Our results demonstrate the coupling between different moiré quantum properties and will hold great promise for new moiré physics and applications.
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2023, Vol. 40 
