Anderson localization of electron states in Al-Pd-Re quasicrystal
ORAL
Abstract
The influence of disorder on the critical electron states in a quasiperiodic lattice is a subject of intense research. In this work, we apply using hard x-ray photoelectron spectroscopy, density functional theory and resistivity to establish occurrence of Anderson localization in a so-called "semiconducting" icosahedral quasicrystal Al-Pd-Re due to site disorder. Anderson localization is observed in polygrain Al-Pd-Re, whose conductivity is an order of magnitude reduced compared to the single-grain monocrystalline Al-Pd-Re. Curiously however, the spectral intensity of the localized electron states is enhanced at the Fermi level in the former. These extra states originate primarily from Re 5d- Pd 4d hybridization, and are enhanced in polygrain i-Al-Pd-Re due to compositional difference, but are broadened because of disorder that brings about Anderson localization. This is established by the Mott variable range hopping behavior of conductivity, and the estimated localization length is 23 Å. In contrast, the spectral shape of sg-Al-Pd-Re portrays a well-formed pseudogap, and exhibits excellent agreement with the valence band calculated for ordered Al-Pd-Re, indicating absence of anderson localization.
*Financial support by the DST, government of India, within the framework of India@DESY collaboration is gratefully acknowledged. M.K. thanks the Slovak Grant Agency VEGA (Grant No. 2/0082/17, 2/0144/21) and APVV (Grant No. 19-0369) for support. Part of the calculations was performed at the Computing Center of the Slovak Academy of Sciences using the supercomputing infrastructure acquired in Projects No. ITMS 26230120002 and No. 26210120002.
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Publication: Phys. Rev. B 103, L241106 (2021)
Presenters
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Sudipta Roy Barman
- UGC-DAE Consortium for Scientific Research
- UGC-DAE Consortium for Scientific Research, Khandwa Road, Indore 452001, Madhya Pradesh, India
- UGC-DAE Consortium for Scientific Research, India