Topological Dirac States beyond π-Orbitals for Silicene on SiC(0001) Surface.
basic_science · Level V
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- Record sourced from PubMed, PMID 28960082.
- Also identified by DOI 10.1021/acs.nanolett.7b02855.
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Abstract
The discovery of intriguing properties related to the Dirac states in graphene has spurred huge interest in exploring its two-dimensional group-IV counterparts, such as silicene, germanene, and stanene. However, these materials have to be obtained via synthesizing on substrates with strong interfacial interactions, which usually destroy their intrinsic π(p<sub>z</sub>)-orbital Dirac states. Here we report a theoretical study on the existence of Dirac states arising from the p<sub>x,y</sub> orbitals instead of p<sub>z</sub> orbitals in silicene on 4H-SiC(0001), which survive in spite of the strong interfacial interactions. We also show that the exchange field together with the spin-orbital coupling give rise to a detectable band gap of 1.3 meV. Berry curvature calculations demonstrate the nontrivial topological nature of such Dirac states with a Chern number C = 2, presenting the potential of realizing quantum anomalous Hall effect for silicene on SiC(0001). Finally, we construct a minimal effective model to capture the low-energy physics of this system. This finding is expected to be also applicable to germanene and stanene and imply great application potentials in nanoelectronics.