Fraction of delocalized eigenstates in the long-range Aubry-André-Harper model

Autor: Nilanjan Roy, Auditya Sharma
Rok vydání: 2021
Předmět:
Zdroj: Physical Review B. 103
ISSN: 2469-9969
2469-9950
DOI: 10.1103/physrevb.103.075124
Popis: We uncover a systematic structure in the single particle phase-diagram of the quasiperiodic Aubry-Andr\'e-Harper(AAH) model with power-law hoppings ($\sim \frac{1}{r^\sigma}$) when the quasiperiodicity parameter is chosen to be a member of the `metallic mean family' of irrational Diophantine numbers. In addition to the fully delocalized and localized phases we find a co-existence of multifractal (localized) states with the delocalized states for $\sigma1$). The fraction of delocalized eigenstates in these phases can be obtained from a general sequence, which is a manifestation of a mathematical property of the `metallic mean family'. The entanglement entropy of the noninteracting many-body ground states respects the area-law if the Fermi level belongs in the localized regime while logarithmically violating it if the Fermi-level belongs in the delocalized or multifractal regimes. The prefactor of logarithmically violating term shows interesting behavior in different phases. Entanglement entropy shows the area-law even in the delocalized regime for special filling fractions, which are related to the metallic means.
Comment: 10 pages, 13 figures
Databáze: OpenAIRE