Intriguing Behavior of Halogenated Two-Dimensional Tin

By means of first-principles calculations, we investigate the effect of halogens on the electronic properties of two-dimensional tin. We found the following: (1) In contrast to the currently accepted view that the Dirac cone characteristic would be deformed upon chemisorption, a new Dirac conelike characteristic of halogenated two-dimensional tin forms at the Fermi level; therefore, almost every significant property of two-dimensional tin could be transferred to halogenated two-dimensional tin with the extra advantage of being easily fabricated in experiments. (2) More surprisingly, upon chemisorption of F, Cl, Br, and I, the magnitude of the spin orbit-induced gap can exceed those in all the currently predicated 2D materials by several orders of magnitude.