4,843 research outputs found
Kondo Metal and Ferrimagnetic Insulator on the Triangular Kagom\'e Lattice
We obtain the rich phase diagrams in the Hubbard model on the triangular
Kagom\'e lattice as a function of interaction, temperature and asymmetry, by
combining the cellular dynamical mean-field theory with the continuous time
quantum Monte Carlo method. The phase diagrams show the asymmetry separates the
critical points in Mott transition of two sublattices on the triangular
Kagom\'e lattice and produces two novel phases called plaquette insulator with
an obvious gap and a gapless Kondo metal. When the Coulomb interaction is
stronger than the critical value Uc, a short range paramagnetic insulating
phase, which is a candidate for the short rang resonating valence-bond spin
liquid, emerges before the ferrimagnetic order is formed independent of
asymmetry. Furthermore, we discuss how to measure these phases in future
experiments
Topological Dirac states beyond orbitals for silicene on SiC(0001) surface
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
()-orbital Dirac states. Here we report a theoretical study on the
existence of Dirac states arising from the orbitals instead of
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 , 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.Comment: 6 Figures , Accepted by Nano Letter
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