Quasi-coherency of electronic states in Ga(As, P) fractal structured lattice

摘要

Electronic states in single crystals (or periodic superlattice) are given by the periodicity, such as Bloch theorem (or Kronig-Penny model). In contrast, Fractal structures are characterized by the non-periodicity with long-range-order, and attracting increasing attention in various fields of research, which is called the complex system. Introducing Fractal structured lattice-arrangement into superlattices, the diffraction peaks are rather sharp, but not really Bragg-like~(1, 2, 3). Considering interference of electrons in such as the superlattice, the electronic states are expected to show singular features due to the quasi-coherency of electrons~(3, 4). Atomic layer epitaxy (ALE) makes a layer-by-layer control of lattice arrangement possible by the self-limiting growth mechanism~(5, 6). From the biggest advantage of ALE, it can be expected that Fractal structures with the flat interfaces and well-crystalline quality are synthesized artificially. We report the results of some optical measurements on electronic states in Ga(As, P) Fractal structured lattice (FSL) grown by ALE, and discuss them in this paper.