Transition metal dichalcogenide-based moiré superlattices exhibit strong electron–electron correlations, thus giving rise to strongly correlated quantum phenomena such as generalized Wigner crystal states. Evidence of Wigner crystals in transition metal dichalcogenide moire superlattices has been widely reported from various optical spectroscopy and electrical conductivity measurements, while their microscopic nature has been limited to the basic lattice structure. Theoretical studies predict that unusual quasiparticle excitations across the correlated gap between upper and lower Hubbard bands can arise due to long-range Coulomb interactions in generalized Wigner crystal states. However, the microscopic proof of such quasiparticle excitations is challenging because of the low excitation energy of the Wigner crystal. Here we describe a scanning single-electron charging spectroscopy technique with nanometre spatial resolution and single-electron charge resolution that enables us to directly image electron and hole wavefunctions and to determine the thermodynamic gap of generalized Wigner crystal states in twisted WS₂ moiré heterostructures. High-resolution scanning single-electron charging spectroscopy combines scanning tunnelling microscopy with a monolayer graphene sensing layer, thus enabling the generation of individual electron and hole quasiparticles in generalized Wigner crystals. We show that electron and hole quasiparticles have complementary wavefunction distributions and that thermodynamic gaps of ∼50 meV exist for the 1/3 and 2/3 generalized Wigner crystal states in twisted WS₂.

基于过渡金属二硫属化物的莫尔超晶格表现出很强的电子-电子相关性，从而产生强相关的量子现象，例如广义维格纳晶态。过渡金属二硫族化物云纹超晶格中维格纳晶体的证据已通过各种光谱学和电导率测量得到广泛报道，而它们的微观性质仅限于基本晶格结构。理论研究预测，由于广义维格纳晶态中的长程库仑相互作用，可能会出现跨越上哈伯德带和下哈伯德带之间的相关间隙的异常准粒子激发。然而，由于维格纳晶体的激发能较低，这种准粒子激发的微观证明具有挑战性。在这里，我们描述了一种具有纳米空间分辨率和单电子电荷分辨率的扫描单电子充电光谱技术，使我们能够直接对电子和空穴波函数进行成像，并确定扭曲 WS ₂莫尔异质结构中广义维格纳晶态的热力学间隙。高分辨率扫描单电子充电光谱将扫描隧道显微镜与单层石墨烯传感层相结合，从而能够在广义维格纳晶体中生成单个电子和空穴准粒子。我们证明电子和空穴准粒子具有互补的波函数分布，并且扭曲 WS ₂中的 1/3 和 2/3 广义维格纳晶态存在~ 50 meV 的热力学间隙。