Correlated electronic phases in twisted bilayer transition metal dichalcogenides
Correlated electronic phases in twisted bilayer transition metal dichalcogenides
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DOI：
10.1038/s41563-020-0708-6
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发表时间：
2020-06-22
期刊：
影响因子：
41.2
通讯作者：
Dean, Cory R.
中科院分区：
文献类型：
--
作者：
Wang, Lei;Shih, En-Min;Dean, Cory R.
在扭曲双层WSe(2)中观察到了在一定扭角范围内的可调谐相关态，扭转角为5.1°时具有超导电性特征。在库仑相互作用能与带宽相当的窄电子带中，相互作用可以驱动新的量子相。在扭曲的石墨烯体系中，这种平带导致了相关的绝缘体、超导和拓扑态。在这里，我们报告了在扭曲的双层WSe2中有低能平带的证据，并在从4度到5.1度的扭角范围内观察到集体相的特征。在半带填充时，出现了可随扭角和位移场调节的相关绝缘体。在5.1度扭转时，观察到在低于3K的温度下，掺杂远离一半填充时出现了零电阻口袋，这表明可能发生了向超导状态的转变。在一个简单的带中观察到的可调集体相，在充满时每个晶胞只有两个空穴，建立了扭曲的双层过渡金属二卤化物作为在三角形晶格上研究二维关联物理的理想平台。
Tunable correlated states are observed in twist bilayer WSe(2)over a range of twist angles, with signatures of superconductivity for a twist of 5.1 degrees.In narrow electron bands in which the Coulomb interaction energy becomes comparable to the bandwidth, interactions can drive new quantum phases. Such flat bands in twisted graphene-based systems result in correlated insulator, superconducting and topological states. Here we report evidence of low-energy flat bands in twisted bilayer WSe2, with signatures of collective phases observed over twist angles that range from 4 to 5.1 degrees. At half-band filling, a correlated insulator appeared that is tunable with both twist angle and displacement field. At a 5.1 degrees twist, zero-resistance pockets were observed on doping away from half filling at temperatures below 3 K, which indicates a possible transition to a superconducting state. The observation of tunable collective phases in a simple band, which hosts only two holes per unit cell at full filling, establishes twisted bilayer transition metal dichalcogenides as an ideal platform to study correlated physics in two dimensions on a triangular lattice.