论文标题

五边形准晶体的本地同构类别中的局部状态

Localized States in Local Isomorphism Classes of Pentagonal Quasicrystals

论文作者

Oktel, M. Ö.

论文摘要

可以通过将五维立方晶格的一部分投射到两个维度来定义五角形准晶体。单个参数,截距$γ= \sum_jγ_j$的总和描述了这个家族。 $ 0 \leγ\ le \ frac {1} {2} $的每个值定义了这些准晶体的唯一局部同构类别,其中$γ= 0 $ $ $提供了Penrose lattice。除了$γ$的一些特殊值之外,这些晶格缺乏简单的通货膨胀量规则,因此很难计算重复给定的本地配置的频率。我们考虑这些准晶体上的顶点结合模型,并针对所有$γ$的所有值研究严格的局部状态(LS)。我们通过在$ 〜10^5 $站点的晶格上以及识别局部状态类型并计算其垂直空间图像的数值精确对角线化来计算局部状态的频率。虽然两分列晶体的sublattices的地点数量之间的不平衡以$γ$的形式单调增长,但我们发现局部态分数首先减少,然后随着距Penrose Lattice的距离而增加。最高的LS分数为$ 〜10.17 \%$,以$γ= 0.5 $的价格达到,而最低为$ 〜4.5 \%$ $ at $γ\ simeq 0.12 $。偶数sublattice上的LS通常集中在具有高对称性的位置附近,而奇数sublattice上的LS则更均匀地分布。奇数sublatice的LS分数较高,几乎是Sublattice的LS频率的三倍,$γ= 0.5 $。我们在均匀的Sublatice上识别20种LS类型,它们的总频率与所有值的数值精确对角线化结果非常吻合。对于奇数sublattice,我们确定了45 ls类型。但是,它们的总频率显着低于数值计算,表明更独立的LS类型的可能性。

A family of pentagonal quasicrystals can be defined by projecting a section of the five-dimensional cubic lattice to two dimensions. A single parameter, the sum of intercepts $Γ=\sum_j γ_j$, describes this family. Each value of $0\le Γ\le \frac{1}{2}$ defines a unique local isomorphism class for these quasicrystals, with $Γ=0$ giving the Penrose lattice. Except for a few special values of $Γ$, these lattices lack simple inflation-deflation rules making it hard to count how frequently a given local configuration is repeated. We consider the vertex-tight-binding model on these quasicrystals and investigate the strictly localized states (LS) for all values of $Γ$. We count the frequency of localized states both by numerical exact diagonalization on lattices of $~10^5$ sites and by identifying localized state types and calculating their perpendicular space images. While the imbalance between the number of sites of the sublattices of the bipartite quasicrystal grows monotonically with $Γ$, we find that the localized state fraction first decreases and then increases as the distance from the Penrose lattice grows. The highest LS fraction of $~10.17\%$ is attained at $Γ=0.5$ while the minimum is $~4.5\%$ at $Γ\simeq 0.12$. The LS on the even sublattice are generally concentrated near sites with high symmetry, while the LS on the odd sublattice are more uniformly distributed. The odd sublattice has a higher LS fraction, having almost three times the LS frequency of the even sublattice at $Γ=0.5$. We identify 20 LS types on the even sublattice, and their total frequency agrees well with the numerical exact diagonalization result for all values of $Γ$. For the odd sublattice, we identify 45 LS types. However, their total frequency remains significantly below the numerical calculation, indicating the possibility of more independent LS types.

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