Defect solitons supported by parity-time symmetric defect in superlattices
Hu Su-Mei (胡素梅)a, Hu Wei (胡巍)b
a Department of Physics, Guangdong University of Petrochemical Technology, Maoming 525000, China; b Laboratory of Photonic Information Technology, South China Normal University, Guangzhou 510631, China
Abstract The existence and stability of defect solitons supported by parity-time (PT) symmetric defects in superlattices are investigated. In the semi-infinite gap, in-phase solitons are found to exist stably for positive defects, zero defects, and negative defects. In the first gap, out-of-phase solitons are stable for positive defects or zero defects, whereas in-phase solitons are stable for negative defects. For both the in-phase and out-of-phase solitons with the positive defect and in-phase solitons with negative defect in the first gap, there exists a cutoff point of the propagation constant below which the defect solitons vanish. The value of the cutoff point depends on the depth of defect and the imaginary parts of the PT symmetric defect potentials. The influence of the imaginary part of the PT symmetric defect potentials on soliton stability is revealed.
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