Squeezed metallic droplet with tunable Kubo gap and charge injection in transition metal dichalcogenides
Jiaren Yuan, Yuanping Chen, Yuee Xie, Xiaoyu Zhang, Dewei Rao, Yan-Dong Guo, Xiaohong Yan, Yuan Ping Feng, Yongqing Cai
Abstract
Shrinking the size of a bulk metal into nanoscale leads to the discreteness of electronic energy levels, the so-called Kubo gap δ. Renormalization of the electronic properties with a tunable and size-dependent δ renders fascinating photon emission and electron tunneling. In contrast with usual three-dimensional (3D) metal clusters, here we demonstrate that Kubo gap δ can be achieved with a two-dimensional (2D) metallic transition metal dichalcogenide (i.e., 1T′-phase MoTe 2 ) nanocluster embedded in a semiconducting polymorph (i.e., 1H-phase MoTe 2 ). Such a 1T′/1H MoTe 2 nanodomain resembles a 3D metallic droplet squeezed in a 2D space which shows a strong polarization catastrophe while simultaneously maintaining its bond integrity, which is absent in traditional δ-gapped 3D clusters. The weak screening of the host 2D MoTe 2 leads to photon emission of such pseudometallic systems and a ballistic injection of carriers in the 1T′/1H/1T′ homojunctions which may find applications in sensors and 2D reconfigurable devices.