Cai Min, Jiang Zeyu, Liao Wen-Ao, Qin Hao-Jun, Zhang Wen-Hao, Zhou Jian-Wang, Liu Li-Si, Liang Yunfan, West Damien, Zhang Shengbai, Fu Ying-Shuang
School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, China.
Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, NY, USA.
Nat Commun. 2025 Aug 2;16(1):7117. doi: 10.1038/s41467-025-62552-w.
Manipulating electrons opens up emerging synthetic strategies. Multipolaron, as a rare quasiparticle containing multiple excess charges collectively dressed with shared local lattice distortions, provides an ideal medium for electron manipulation, yet remains elusive. Here, with scanning tunneling microscopy, we realize electron multipolarons in monolayer CrBr. The multipolaron is crafted via assembling single monopolarons with the tip, allowing their electron numbers to increase one-by-one controllably. With added electrons, the multipolaron exhibits stronger local band bending and upward shift of the polaronic states. Notably, the apparent charge of the multipolaron can be reduced by tip manipulation. First principles calculations reveal that the multipolaron is stabilized by large diffusion barriers and screening of the substrate. The apparent charge reduction is attributed to the formation of the polaron-exciton droplet where the multipolaron captures holes from the substrate to partially offset the Coulomb repulsion. Our findings establish an approach for studying polaron interactions at the atomic limit.
操控电子开启了新兴的合成策略。多极化子作为一种罕见的准粒子，包含多个多余电荷，并集体伴有共享的局部晶格畸变，为电子操控提供了理想介质，但仍然难以捉摸。在此，我们利用扫描隧道显微镜在单层CrBr中实现了电子多极化子。通过用针尖组装单个单极化子来制造多极化子，从而使其电子数可控地逐个增加。随着电子的添加，多极化子表现出更强的局部能带弯曲和极化子态的向上移动。值得注意的是，多极化子的表观电荷可以通过针尖操控来降低。第一性原理计算表明，多极化子通过大的扩散势垒和衬底的屏蔽作用而稳定。表观电荷的减少归因于极化子 - 激子液滴的形成，其中多极化子从衬底捕获空穴以部分抵消库仑排斥力。我们的发现建立了一种在原子极限下研究极化子相互作用的方法。
