Feng Runfa, Wang Wei, Bao Changhua, Zhang Zichun, Wang Fei, Zhang Hongyun, Yao Junjie, Xu Yong, Yu Pu, Ji Shuai-Hua, Si Chen, Zhou Shuyun
State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, P. R. China.
School of Materials Science and Engineering, Beihang University, Beijing, 100084, P. R. China.
Adv Mater. 2024 Jan;36(3):e2302297. doi: 10.1002/adma.202302297. Epub 2023 Dec 2.
Transition metal dichalcogenide (TMDC) films exhibit rich phases and superstructures, which can be controlled by the growth conditions as well as post-growth annealing treatment. Here, the selective growth of monolayer TaTe films with different phases as well as superstructures using molecular beam epitaxy (MBE) is reported. Monolayer 1H-TaTe and 1T-TaTe films can be selectively controlled by varying the growth temperature, and their different electronic structures are revealed through the combination of angle-resolved photoemission spectroscopy measurements (ARPES) and first-principles calculations. Moreover, post-growth annealing of the 1H-TaTe film further leads to a transition from a superstructure to a new 2 × 2 superstructure, where two gaps are observed in the electronic structure and persist up to room temperature. First-principles calculations reveal the role of the phonon instability in the formation of superstructures and the effect of local atomic distortions on the modified electronic structures. This work demonstrates the manipulation of the rich phases and superstructures of monolayer TaTe films by controlling the growth kinetics and post-growth annealing.
过渡金属二硫属化物（TMDC）薄膜展现出丰富的相和超结构，这些可通过生长条件以及生长后的退火处理来控制。在此，报道了使用分子束外延（MBE）选择性生长具有不同相和超结构的单层TaTe薄膜。通过改变生长温度可选择性地控制单层1H-TaTe和1T-TaTe薄膜，并且通过角分辨光电子能谱测量（ARPES）与第一性原理计算相结合揭示了它们不同的电子结构。此外，1H-TaTe薄膜生长后的退火进一步导致从一种超结构转变为新的2×2超结构，在该电子结构中观察到两个能隙，并且这些能隙一直持续到室温。第一性原理计算揭示了声子不稳定性在超结构形成中的作用以及局部原子畸变对改性电子结构的影响。这项工作展示了通过控制生长动力学和生长后退火来操纵单层TaTe薄膜丰富的相和超结构。
