Scanning tunneling microscopy of Bi$_2$Te$_3$ films prepared by pulsed laser deposition: from nanocrystalline structures to van der Waals epitaxy

• Main Authors: Fedotov, N. I, Maizlakh, A. A, Pavlovskiy, V. V, Rybalchenko, G. V, Zaitsev-Zotov, S. V
• Format: Journal Article
• Language: English
• Published: 13.03.2022
• Subjects: Physics - Materials Science
• DOI: 10.48550/arxiv.2203.06734

Bi$_2$Te$_3$ is a material with high efficiency of thermoelectric energy conversion. Recently, it was also recognized as a topological insulator, and is often used as the basis for creation of other types of topological matter. Pulsed laser deposition (PLD) is widely considered as a simple method for growing of multicomponent films, but not as a tool for van der Waals epitaxy. We demonstrate here that the van der Waals epitaxy of Bi$_2$Te$_3$ is indeed impossible in vacuum PLD, but is possible in the presence of a background gas, which is confirmed by the results of scanning tunneling microscopy and spectroscopy studies. Results of {\it ab initio} calculations reproduce tunneling spectra of the first three terraces of epitaxial films of Bi$_2$Te$_3$. In addition, an unusual hexagonal superstructure resembling a charge-density wave is observed in overheated films.