Atomically Resolved Electronic Structure in Two-Dimensional Chromium Triiodide

• Main Authors: Chao-Hsiang Chang, 張朝翔
• Other Authors: Ya-Ping Chiu
• Format: Others
• Language: en_US
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/qx5dhp

碩士 === 國立臺灣大學 === 物理學研究所 === 107 === Monolayer Chromium Triiodide (CrI3), being the thinnest ferromagnetic material, has recently received significant attention because of a low Curie temperature ~ 45 K. Until now, most studies focus on the magnetic properties and crystal structure of CrI3. ¬However, the real-space image and the fundamental electronic structure is still missing. Here, we utilize scanning tunneling microscopy and spectroscopy (STM/S) to investigate both the direct atomic surface structure and the density of states of CrI3 at room temperature. Results show that the crystal structure is monoclinic (C2/m), consistent with the previous studies. Moreover, the electronic properties of CrI3 have two main features. We measure the band gap of CrI3 and observe that the tunneling currents in the conduction band, which are determined from Chromium atoms, act more obviously than they do in the valance band. The other, the defects of CrI3 result in the band gap narrowing.