تقرير
Tail states and unusual localization transition in low-dimensional Anderson model with power-law hopping
العنوان: | Tail states and unusual localization transition in low-dimensional Anderson model with power-law hopping |
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المؤلفون: | Tikhonov, Konstantin S., Ioselevich, Alexey S., Feigel'man, Mikhail V. |
سنة النشر: | 2021 |
المجموعة: | Condensed Matter |
مصطلحات موضوعية: | Condensed Matter - Disordered Systems and Neural Networks |
الوصف: | We study deterministic power-law quantum hopping model with an amplitude $J(r) \propto - r^{-\beta}$ and local Gaussian disorder in low dimensions $d=1,2$ under the condition $d < \beta < 3d/2$. We demonstrate unusual combination of exponentially decreasing density of the "tail states" and localization-delocalization transition (as function of disorder strength $w$) pertinent to a small (vanishing in thermodynamic limit) fraction of eigenstates. At sub-critical disorder $w < w_c$ delocalized eigenstates with energies near the bare band edge co-exist with a strongly localized eigenstates in the same energy window. At higher disorder $w > w_c$ all eigenstates are localized. In a broad range of parameters density of states $\nu(E)$ decays into the tail region $E <0$ as simple exponential, $ \nu(E) = \nu_0 e^{E/E_0} $, while characteristic energy $E_0$ varies smoothly across edge localization transition. We develop simple analytic theory which describes $E_0$ dependence on power-law exponent $\beta$, dimensionality $d$ and disorder strength $W$, and compare its predictions with exact diagonalization results. At low energies within the bare "conduction band", all eigenstates are localized due to strong quantum interference at $d=1,2$; however localization length grows fast with energy decrease, contrary to the case of usual Schrodinger equation with local disorder. |
نوع الوثيقة: | Working Paper |
DOI: | 10.1016/j.aop.2021.168524 |
URL الوصول: | http://arxiv.org/abs/2103.06001 |
رقم الأكسشن: | edsarx.2103.06001 |
قاعدة البيانات: | arXiv |
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