3,119 research outputs found
Proximity-induced topological phases in bilayer graphene
We study the band structure of phases induced by depositing bilayer graphene
on a transition metal dichalcogenide monolayer. Tight-binding and low-energy
effective Hamiltonian calculations show that it is possible to induce
topologically nontrivial phases that should exhibit spin Hall effect in these
systems. We classify bulk insulating phases through calculation of the Z
invariant, which unequivocally identifies the topology of the structure. The
study of these and similar hybrid systems under applied gate voltage opens the
possibility for tunable topological structures in real experimental systems.Comment: 4 pages, 4 figure
Selective coherent destruction of tunneling in a quantum-dot array
The coherent manipulation of quantum states is one of the main tasks required
in quantum computation. In this paper we demonstrate that it is possible to
control coherently the electronic position of a particle in a quantum-dot
array. By tuning an external ac electric field we can selectively suppress the
tunneling between dots, trapping the particle in a determined region of the
array. The problem is treated non-perturbatively by a time-dependent
Hamiltonian in the effective mass approximation and using Floquet theory. We
find that the quasienergy spectrum exhibits crossings at certain field
intensities that result in the selective suppression of tunneling.Comment: 4 pages, 5 figures, submitted to PRB Rapid Com
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