A New Family of Two-Dimensional Crystals: Open-Framework T<sub>3</sub> X ( T = C, Si, Ge, Sn; X = O, S, Se, Te) Compounds with Tetrahedral Bonding.

Chae, Kisung; Son, Young-Woo · Nano Lett · 2019

basic_science · Level V

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Abstract

To accelerate development of innovative materials, their modelings and predictions with useful functionalities are of vital importance. Here, based on a recently developed crystal structure prediction method, we find a new family of stable two-dimensional crystals with an open-channel tetrahedral bonding network, rendering a potential prototype for electronic and energy applications. The proposed structural prototype with a space group of Cmme hosts at least 13 different freestanding T<sub>3</sub> X compounds with group IV ( T = C, Si, Ge, Sn) and VI ( X = O, S, Se, Te) elements. Moreover, the proposed materials display diverse electronic properties ranging from direct band gap semiconductor to topological insulator at their pristine forms, which are further tunable by mechanical strain.