Evidence for a marginally conducting state in AlCuFe and AlPdMn quasicrystals

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• 作者：Triozon ; Francois ; Mayou ; Didier
• 关键词：E255 ; O050 ; O110 ; Q110 ; T130 ; 71.23.Ft ; 72.15.&minus ; v ; 78.20.&minus ; e
• 刊名：Journal of Non-Crystalline Solids
• 出版年：2004
• 出版时间：March 15, 2004
• 年：2004
• 卷：334-335
• 期：Complete
• 页码：376-379
• 全文大小：272 K

文摘

In a quasiperiodic system without defects the dissipative part of the conductivity is expected to vary as Reσ₀(ω)ω^1−2β at low frequency ω(0<β<1). β is the diffusion exponent in the perfect structure such that the spreading of wavepackets is L(t)t^β at large time t. Under certain conditions disorder induces a current relaxation in a time τ and we express the conductivity, with defects, in terms of τ and of the conductivity without defects, Reσ₀(ω). For AlCuFe and AlPdMn quasicrystals a coherent interpretation of the conduction properties is obtained. We extract the values of τ and get β0. It means that quantum diffusion is slow or marginal in the perfect systems.