Topological Insulator Superlattices via Spinodal Decomposition*

Advanced thermodynamic and electronic structure concepts are combined to define a design strategy for topological insulator superlattices – an alternative to the costly and time-consuming experimental artificial growth methods [1]. Stabilizing self-assembled interfaces between iso-structural and iso-valent topological insulators is possible through spinodal decomposition. To investigate the composition range guaranteeing the topologically protected gapless metallic states, various thermodynamically driven boundaries are designed between constituent materials. The dimensions and topological nature of the metallic channels are tracked by following the spatial distribution of the charge density and spin-texture. The results validate the proof of concept for obtaining spontaneously forming two-dimensional topologically protected metallic states embedded in a three-dimensional insulating environment without any vacuum interfaces.

[1] D. Usanmaz, P. Nath, C. Toher, J. J. Plata, R. Friedrich, M. Fornari, M. Buongiorno Nardelli, and S. Curtarolo, Chem. Mater. 2018, 30, 2331−2340.