Finite-size effects in non-Hermitian topological systems
Abstract
We systematically investigate the finite-size effects in non-Hermitian one-dimensional Su-Schrieffer-Heeger (SSH) and two-dimensional (2D) Chern insulator models. In the Hermitian SSH system, the finite-size energy gap is always real and shows a monotonic-exponential decay as the chain length grows. In contrast, for the non-Hermitian SSH model, the non-Hermitian intracell hoppings can modify the localization lengths of bulk and end states, giving rise to a complex finite-size energy gap that exhibits an oscillating exponential decay as the chain length grows. However, the imaginary staggered onsite potentials in the SSH model only change the end-state energy, leaving the localization lengths of the system unchanged. In this case, the finite-size energy gap can undergo a transition from real values to imaginary values. We observed similar phenomena for the finite-size effect in 2D non-Hermitian Chern insulator systems.
- Publication:
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Physical Review B
- Pub Date:
- April 2019
- DOI:
- arXiv:
- arXiv:1901.06820
- Bibcode:
- 2019PhRvB..99o5431C
- Keywords:
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- Condensed Matter - Mesoscale and Nanoscale Physics
- E-Print:
- 12 pages, 12 figures. Accepted by Physical Review B