近日,
本文报道了一项关于在扭曲双层二硫化钨莫尔超晶格中,由多电子人工原子构成的维格纳分子晶体的实验观测结果。通过应用扫描隧道显微镜技术,研究人员证实了,在库仑相互作用占据主导地位的情况下,多电子人工原子内能够形成维格纳分子。在超晶格内观察到的维格纳分子阵列展现出了一种电子的结晶相——即维格纳分子晶体,这种晶体通过机械应变、莫尔周期以及载流子电荷类型的调整,展现出了高度可调的特性。
据悉,半导体莫尔纳米超晶格提供了一个通用的平台,可以在莫尔纳米位置上设计由人工原子组成的量子固体。先前的研究主要集中在最简单的相关量子固体上——费米-哈伯德模型——其中原子内相互作用被简化为一个单一的现场排斥能U。
附:英文原文
Title: Wigner molecular crystals from multielectron moiré artificial atoms
Author: Hongyuan Li, Ziyu Xiang, Aidan P. Reddy, Trithep Devakul, Renee Sailus, Rounak Banerjee, Takashi Taniguchi, Kenji Watanabe, Sefaattin Tongay, Alex Zettl, Liang Fu, Michael F. Crommie, Feng Wang
Issue&Volume: 2024-07-05
Abstract: Semiconductor moiré superlattices provide a versatile platform to engineer quantum solids composed of artificial atoms on moiré sites. Previous studies have mostly focused on the simplest correlated quantum solid—the Fermi-Hubbard model—in which intra-atom interactions are simplified to a single onsite repulsion energy U. Here we report the experimental observation of Wigner molecular crystals emerging from multielectron artificial atoms in twisted bilayer tungsten disulfide moiré superlattices. Using scanning tunneling microscopy, we demonstrate that Wigner molecules appear in multielectron artificial atoms when Coulomb interactions dominate. The array of Wigner molecules observed in a moiré superlattice comprises a crystalline phase of electrons: the Wigner molecular crystal, which is shown to be highly tunable through mechanical strain, moiré period, and carrier charge type.
Source: https://www.science.org/doi/10.1126/science.adk1348