We propose a generalization of the Su-Schrieffer-Heeger (SSH) model of the bipartite lattice, consisting of a periodic array of domain walls. The low-energy description is governed by the superposition of localized states at each domain wall, forming an effective mono-atomic chain at a larger scale. When the domain walls are dimerized, topologically protected edge states can appear, just like in the original SSH model. These new edge states are formed exclusively by soliton-like states and therefore, the new topological states are qualitatively different from the regular SSH edge states. They posses a much longer localization length and are more resistant to on-site disorder, in marked contrast to the standard SSH case.
Research on topological insulators has experienced an exponential growth in the last few years. An easy to grasp understanding of their properties is presented for chemists.
This article presents a chemical description of a simple topological insulators model in order to translate concepts such as "symmetry protected", "surface states" to the chemistry vocabulary
This article presents a chemical description of a simple topological insulators model in order to translate concepts such as "symmetry protected", "surface states" to the chemistry vocabulary
Most single photon emitters in hexagonal boron nitride has been identified as carbon substitutional defects, forming donor-acceptor systems. Unlike the most studied bulk emitters (i.e. color centers in diamond), these defects have no net spin, or have a single unpaired spin. By means of density functional calculations, we show that two non-adjacent carbon substitutional defects of the same type (i.e. CBCB}, and CNCN), can have a triplet ground state. In particular, one of such defects has a zero phonon line energy of 2.5 eV, and its triplet state is nearly 0.5 eV more stable than its singlet. The mechanism behind the destabilization of the singlet state is related to a larger electrostatic repulsion of a symmetric wave function in a charged lattice.
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