Dipolar excitonic insulator in a moire lattice
Dipolar excitonic insulator in a moire lattice
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DOI：
10.1038/s41567-022-01532-z
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发表时间：
2022-03-10
期刊：
影响因子：
19.6
通讯作者：
Mak, Kin Fai
中科院分区：
文献类型：
--
作者：
Gu, Jie;Ma, Liguo;Mak, Kin Fai
二维云纹材料为量子现象的研究提供了一个高度可控的固态平台（1-3）。迄今为止，实验研究主要集中在相关电子态上，而云纹材料中相关玻色子态的研究较少。在这里，我们报告了在WSe2单层和WSe2/WS2云纹双层通过库仑相互作用耦合的装置中观察到的相关偶极激子绝缘体-由激子形成驱动的电荷绝缘状态(4)。当所有的空穴都位于云纹层时，系统是莫特绝缘体。在面外电场作用下，空穴可以连续地转移到WSe2单层中，但仍与空的云纹位紧密结合，有效地在云纹晶格中形成层间激子流体。我们进一步观察到WSe2单层中出现了由层间强库仑相关引起的局部磁矩。我们的结果为在固态系统中实现由玻色子晶格模型描述的相关量子现象提供了一个平台，补充了冷原子的设置(5)。
Two-dimensional moire materials provide a highly controllable solid-state platform for studies of quantum phenomena(1-3). To date, experimental studies have focused on correlated electronic states, whereas correlated bosonic states in moire materials have received less attention. Here we report the observation of a correlated dipolar excitonic insulator-a charge-insulating state driven by exciton formation(4)-in a device where a WSe2 monolayer and WSe2/WS2 moire bilayer are coupled via Coulomb interactions. The system is a Mott insulator when all the holes reside in the moire layer. Under an out-of-plane electric field, the holes can be continuously transferred to the WSe2 monolayer, but remain strongly bound to the empty moire sites, effectively forming an interlayer exciton fluid in the moire lattice. We further observe the emergence of local magnetic moments in the WSe2 monolayer induced by the strong interlayer Coulomb correlation. Our result provides a platform for realizing correlated quantum phenomena described by bosonic lattice models in a solid-state system, complementary to cold-atom setups(5).