Yuan Long, Zheng Biyuan, Zhao Qiuchen, Kempt Roman, Brumme Thomas, Kuc Agnieszka B, Ma Chao, Deng Shibin, Pan Anlian, Huang Libai
Department of Chemistry, Purdue University, West Lafayette, Indiana 47906, United States.
Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230052, China.
ACS Nano. 2023 Aug 22;17(16):15379-15387. doi: 10.1021/acsnano.2c12903. Epub 2023 Aug 4.
Repulsive and long-range exciton-exciton interactions are crucial for the exploration of one-dimensional (1D) correlated quantum phases in the solid state. However, the experimental realization of nanoscale confinement of a 1D dipolar exciton has thus far been limited. Here, we demonstrate atomically precise lateral heterojunctions based at transitional-metal dichalcogenides (TMDCs) as a platform for 1D dipolar excitons. The dynamics and transport of the interfacial charge transfer excitons in a type II WSe-WSSe lateral heterostructure were spatially and temporally imaged using ultrafast transient reflection microscopy. The expansion of the exciton cloud driven by dipolar repulsion was found to be strongly density dependent and highly anisotropic. The interaction strength between the 1D excitons was determined to be ∼3.9 × 10 eV cm, corresponding to a dipolar length of 310 nm, which is a factor of 2-3 larger than the interlayer excitons at two-dimensional van der Waals vertical interfaces. These results suggest 1D dipolar excitons with large static in-plane dipole moments in lateral TMDC heterojunctions as an exciting system for investigating quantum many-body physics.
排斥性的长程激子-激子相互作用对于探索固态中的一维（1D）相关量子相至关重要。然而，迄今为止，一维偶极激子的纳米级限制的实验实现仍然有限。在这里，我们展示了基于过渡金属二硫属化物（TMDCs）的原子精确横向异质结作为一维偶极激子的平台。使用超快瞬态反射显微镜对II型WSe-WSSe横向异质结构中界面电荷转移激子的动力学和输运进行了空间和时间成像。发现由偶极排斥驱动的激子云扩展强烈依赖于密度且高度各向异性。确定一维激子之间的相互作用强度约为3.9×10 eV cm，对应于310 nm的偶极长度，这比二维范德华垂直界面处的层间激子大2-3倍。这些结果表明，横向TMDC异质结中具有大静态面内偶极矩的一维偶极激子是研究量子多体物理的一个令人兴奋的系统。
