2,363 research outputs found
Bound States of Conical Singularities in Graphene-Based Topological Insulators
We investigate the electronic structure induced by wedge-disclinations
(conical singularities) in a honeycomb lattice model realizing Chern numbers
. We establish a correspondence between the bound state of (i) an
isolated -flux, (ii) an isolated pentagon or heptagon
defect with an external flux of magnitude through
the center and (iii) an isolated square or octagon defect without external
flux, where is the flux quantum. Due to the above correspondence,
the existence of isolated electronic states bound to the disclinations is
robust against various perturbations. These results are also generalized to
graphene-based time-reversal invariant topological insulators.Comment: 5+4 pages, 4+3 figures, revised introduction and Fig.
Dynamical Unbinding Transition in a Periodically Driven Mott Insulator
We study the double occupancy in a fermionic Mott insulator at half-filling
generated via a dynamical periodic modulation of the hopping amplitude. Tuning
the modulation amplitude, we describe a crossover in the nature of
doublon-holon excitations from a Fermi Golden Rule regime to damped Rabi
oscillations. The decay time of excited states diverges at a critical
modulation strength, signaling the transition to a dynamically bound
non-equilibrium state of doublon-holon pairs. A setup using a fermionic quantum
gas should allow to study the critical exponents.Comment: 4 pages, 2 figure
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