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Nonlinear excitations and bound states of electrons, holes and solitons in bilayers of triangular lattices

Chetverikov, Alexander P.; Ebeling, Werner; Schöll, Eckehard; Velarde, Manuel G.

We study the temporal and spatial nonlinear dynamical evolution of a coupled triangular lattice crystal bilayer system where in one layer one excess free electron is injected while an excess positive charge, a hole, is created in the other. The atoms of each of the backbone lattices interact with anharmonic (short range) Morse potentials whereas the charges interact via (long range) Coulomb potentials. Computer simulations are provided of the possibilities offered by varying interlayer separation, strength of the Coulomb force between the charges and the diverse dynamical role played by excited solitons supersonically moving along crystallographic axes in one of the layers. Optimal conditions are identified for the occurrence of electron–hole pairs and for the more significant case of a boson-like electron–hole–soliton coupled compound, a new form of quasiparticle moving along the coupled bilayer system with no need of applying an external electric field.
Published in: European Physical Journal B, 10.1140/epjb/e2019-90715-8, Springer-Verlag GmbH [u.a.]