Su-Schrieffer-Heeger chain with one pair of $$\mathcal{P}\mathcal{T}$$ š¯’« š¯’Æ -symmetric defects
Abstract The topologically nontrivial edge states induce $$\mathcal{P}\mathcal{T}$$ š¯’« š¯’Æ transition in Su-Schrieffer-Heeger (SSH) chain with one pair of gain and loss at boundaries. In this study, we investigated a pair of $$\mathcal{P}\mathcal{T}$$ š¯’« š¯’Æ -symmetric defects located inside the SSH chain...
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| Main Authors: | , , |
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| Format: | article |
| Language: | EN |
| Published: |
Nature Portfolio
2017
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| Subjects: | |
| Online Access: | https://doaj.org/article/7585dda186dc41c181d651aa7d77608d |
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| Summary: | Abstract The topologically nontrivial edge states induce $$\mathcal{P}\mathcal{T}$$ š¯’« š¯’Æ transition in Su-Schrieffer-Heeger (SSH) chain with one pair of gain and loss at boundaries. In this study, we investigated a pair of $$\mathcal{P}\mathcal{T}$$ š¯’« š¯’Æ -symmetric defects located inside the SSH chain, in particular, the defects locations are at the chain centre. The $$\mathcal{P}\mathcal{T}$$ š¯’« š¯’Æ symmetry breaking of the bound states leads to the $$\mathcal{P}\mathcal{T}$$ š¯’« š¯’Æ transition, the $$\mathcal{P}\mathcal{T}$$ š¯’« š¯’Æ -symmetric phases and the localized states were studied. In the broken $$\mathcal{P}\mathcal{T}$$ š¯’« š¯’Æ -symmetric phase, all energy levels break simultaneously in topologically trivial phase; however, two edge states in topologically nontrivial phase are free from the influence of the $$\mathcal{P}\mathcal{T}$$ š¯’« š¯’Æ -symmetric defects. We discovered $$\mathcal{P}\mathcal{T}$$ š¯’« š¯’Æ -symmetric bound states induced by the $$\mathcal{P}\mathcal{T}$$ š¯’« š¯’Æ -symmetric local defects at the SSH chain centre. The $$\mathcal{P}\mathcal{T}$$ š¯’« š¯’Æ -symmetric bound states significantly increase the $$\mathcal{P}\mathcal{T}$$ š¯’« š¯’Æ transition threshold and coalesce to the topologically protected zero mode with vanishing probabilities on every other site of the left-half chain and the right-half chain, respectively. |
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