Proximity of a metal-insulator transition in icosahedral phases of high structural quality

Klein, T.; Berger, Claire; Mayou, Didier; Cyrot‐Lackmann, F.

doi:10.1103/physrevlett.66.2907

Cited by 254 publications

(104 citation statements)

References 14 publications

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“…This explains their unconventional conduction properties. The α-AlMnSi phase is structurally related to the icosahedral quasicrystalline phase AlMnSi and shares many similar conduction properties with other icosahedral phases such as AlCuFe and AlPdMn and their crystalline approximants [3,4,5]. Thus the present work is relevant for these systems too and gives a strong insight in the so far unexplained properties of this class of materials.…”

Section: Jean-pierre Julien and Didier Mayoumentioning

confidence: 91%

Quantum Transport of Slow Charge Carriers in Quasicrystals and Correlated Systems

2006

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We show that the semi-classical model of conduction breaks down if the mean free path of charge carriers is smaller than a typical extension of their wavefunction. This situation is realized for sufficiently slow charge carriers and leads to a transition from a metallic like to an insulating like regime when scattering by defects increases. This explains the unconventional conduction properties of quasicrystals and related alloys. The conduction properties of some heavy fermions or polaronic systems, where charge carriers are also slow, present a deep analogy.PACS numbers: 72.10. Bg, 61.44.Br, 71.23.Ft The semi-classical Bloch-Boltzmann theory, which plays a fundamental role in our understanding of conduction in solids, has limitations such as for example magnetic and electric breakdown [1] or quantum interferences in the diffusive regime [2] that are well known and have been intensively studied. The present work focuses on another limitation that has received little attention and that occurs when charge carriers have sufficiently small velocities.Indeed the semi-classical theory of conduction in crystals is based on the concept of a charge carrier wavepacket propagating at a velocity V = (1/ )∂E n (k)/∂k, where "E n (k)" is the dispersion relation for band n and wavevector k. The validity of the wave-packet concept requires that the extension L wp of the wave-packet of the charge carrier is smaller than the distance V τ of traveling between two scattering events separated by a time τ . On the contrary, if V τ < L wp , a condition that can be realized by sufficiently slow charge carriers, the semi-classical model breaks down. Here we report on a quantum theory that allows to treat on the same footing the standard regime where the semi-classical approach is valid and the regime of slow charge carriers. We find that when the scattering time τ decreases a transition can occur between a metallic regime for V τ > L wp and an insulating like regime for V τ < L wp . As an example we consider specifically a complex metallic alloy: the α-AlMnSi phase. Ab-initio band structure calculations show that the samples of this system, that have been studied experimentally, are in the small velocity regime V τ < L wp . This explains their unconventional conduction properties. The α-AlMnSi phase is structurally related to the icosahedral quasicrystalline phase AlMnSi and shares many similar conduction properties with other icosahedral phases such as AlCuFe and AlPdMn and their crystalline approximants [3,4,5]. Thus the present work is relevant for these systems too and gives a strong insight in the so far unexplained properties of this class of materials. The concepts developped here open also a new insight in the physics of correlated systems. Indeed recent studies of some heavy fermions or polaronic systems [6,7,8], where charge carriers are also slow, show that their conduction properties present a deep analogy with those described here. In particular a transition is observed from a metallic like regime at low temperature (we...

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Section: Jean-pierre Julien and Didier Mayoumentioning

confidence: 91%

Quantum Transport of Slow Charge Carriers in Quasicrystals and Correlated Systems

2006

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“…Thus, i-AlPdMn samples show a conductivity minimum located at about 40-60 K. 22 A less pronounced minimum is reached at lower temperatures ͑10-20 K͒ in the case of some i-AlCuFe samples. 6,23,24 In Fig. 2 we show the temperature dependence of the thermoelectric power for the same approximant phase.…”

Section: Methodsmentioning

confidence: 99%

“…[2][3][4] In this way, it has been progressively realized that the temperature dependence of electrical conductivity, Hall and Seebeck coefficients, and thermal conductivity, resemble a more semiconductorlike than metallic character. [5][6][7] By the light of these experimental results the fundamental question arises concerning whether these transport anomalies should be mainly attributed ͑or not͒ to the characteristic quasiperiodic order of QCs structure. In this regard, experimental evidence showing that the structural evolution from the amorphous to the quasicrystalline state is accompanied by a parallel evolution of the electronic transport anomalies 8 clearly indicates the importance of short-range effects on the emergence of some transport anomalies.…”

Section: Introductionmentioning

confidence: 99%

Modeling the spectral conductivity ofAl−Mn−Siquasicrystalline approximants: A phenomenological approach

2005

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The electronic structure of a quasicrystalline approximant sample is analyzed by means of a combined study of different experimental transport curves within a phenomenological approach. The main features of the obtained spectral conductivity are discussed and compared to those corresponding to icosahedral quasicrystals. Such a comparison provides interesting clues about the role of quasiperiodic order and of local atomic arrangements in the origin of unusual behaviors in the electrical conductivity and thermopower observed in complex metallic alloys.

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“…">IntroductionA variety of Al-based quasicrystals shows unusual electronic properties which seem to be different from those of metals and semiconductors.One of the most anomalous properties of Al-based quasicrystals is a very low electrical conductivity close to the metal-insulator transition [1,2]. However, there is no evidence for a gap as in semiconductors, and the structure is highly ordered, although it is nonperiodic.…”

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confidence: 99%

Electron Localization and Conduction Mechanism of Icosahedral Quasicrystal Al-Pd-Ru

Sekiyama

Kanazawa

2017

J. Phys.: Conf. Ser.

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Abstract.We have argued the temperature dependence of conductivities of the icosahedral AlPd-Ru quasicrystals from the standpoint of the quasicrystal-like system with sp-d hybridization, using the thermal Green's function technique. IntroductionA variety of Al-based quasicrystals shows unusual electronic properties which seem to be different from those of metals and semiconductors.One of the most anomalous properties of Al-based quasicrystals is a very low electrical conductivity close to the metal-insulator transition [1,2]. However, there is no evidence for a gap as in semiconductors, and the structure is highly ordered, although it is nonperiodic. These are unlike Anderson insulators, where disorder is the reason for a localization of electronic wave function.It has been suggested that the anomalous conductivity of Al-based quasicrystals is due to the combination of a Hume-Rothery pseudogap and the presence of localized states at the Fermi level [3].It has been proposed that the unusual transport properties of Al-based quasicrystals might be much related to hopping processes between wave functions localized inside atomic clusters [4,5].Especially Trambly de Laissardiere et al. [5] argued the creation of virtual bond states due to an icosahedral cluster of transition metal (TM) atoms and an icosahedral cluster of the TM clusters. In addition, in views of the ab initio calculations [6,7], Tamura et al. [8] have suggested strongly the creation of the virtual bond states or confinement of electrons, in the icosahedral clusters of TM atoms.Kanazawa and coworkers [9][10][11][12][13][14][15][16] have considered the transport property in the randomly distributed system of the cluster composed of correlated N number of configurations such as the prolate and oblate rhombohedra, in which the nearest distance between each configuration is ~2π/2k F (the quasicrystal-like state). The quasicrystal-like state is regarded as the system composed of the Gaussian correlated distribution of the icosahedral cluster such as the Bergman type and the Mackay type, which include 2k F -phase shift scattering.Taking into account the mean free path 15~20Å of electrons in quasicrystals, it looks like that the anomalous transport properties of quasicrystals are not directly related to quasicrystal structure in the longer range than the mean free path 15~20Å. Thus the transport property in the quasicrystal-like system might be closely analogous to one in the quasicrystal.Tamura et al. [17] have measured the temperature dependence of the resistivity of the icosahedral Al-Pd-Ru quasicrystals, and 1/0 and 2/1 cubic approximant phases.

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Proximity of a metal-insulator transition in icosahedral phases of high structural quality

Cited by 254 publications

References 14 publications

Quantum Transport of Slow Charge Carriers in Quasicrystals and Correlated Systems

Quantum Transport of Slow Charge Carriers in Quasicrystals and Correlated Systems

Modeling the spectral conductivity ofAl−Mn−Siquasicrystalline approximants: A phenomenological approach

Electron Localization and Conduction Mechanism of Icosahedral Quasicrystal Al-Pd-Ru

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