Optical Conductivity of Insulating Al-Based Alloys: Comparison of Quasiperiodic and Periodic Systems

Basov, D. N.; Pierce, F. S.; Volkov, Pavel A.; Poon, S. J.; Timusk, T.

doi:10.1103/physrevlett.73.1865

Cited by 92 publications

(56 citation statements)

References 17 publications

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“…3,9 The estimated values of Born effective charges, comparable to those of typical ionic insulators, are very much larger than the static ionic charges, which previous calculation 2 has shown to be negligible. In this paper, we report the first-principles calculation of the zone-center phonon frequencies, the Born effective charges, and the dielectric tensor of Al 2 Ru.…”

Section: 78mentioning

confidence: 83%

“…Because of its relatively simple crystal structure, it has been suggested 2,3 that investigation of Al 2 Ru can contribute to the understanding of the pseudogap in the electronic density of states observed in quasicrystals. From first-principles calculations of the bandstructure and charge density performed using linear-muffin-tin-orbitals (LMTO) in the atomic sphere approximation, 2 it has been shown that the fundamental gap results from the hybridization of sp(Al) and d(Ru) states.…”

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confidence: 99%

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Anomalous effective charges and far-IR optical absorption ofAl2Ru from first principles

Öğüt

Rabe

1996

Phys. Rev. B

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For the orthorhombic intermetallic semiconductor Al 2 Ru, the bandstructure, valence charge density, zone center optical phonon frequencies, and Born effective charge and electronic dielectric tensors are calculated using variational density functional perturbation theory with ab initio pseudopotentials and a plane wave basis set. Good agreement is obtained with recent measurements on polycrystalline samples which showed anomalously strong far IR absorption by optical phonons, while analysis of the valence charge density shows that the static ionic charges of Al and Ru are negligible. Hybridization is proposed as the single origin both of the semiconducting gap and the anomalous Born effective charges. Analogous behavior is expected in related compounds such as NiSnZr, PbTe, skutterudites, and Al-transition-metal quasicrystals. 78.30.Hv, 71.20.Lp, 63.20.Dj Typeset using REVT E X 1

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Section: 78mentioning

confidence: 83%

mentioning

confidence: 99%

Anomalous effective charges and far-IR optical absorption ofAl2Ru from first principles

Öğüt

Rabe

1996

Phys. Rev. B

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“…12,13) They possess the orthorhombic TiSi 2 structure, which has the space group Fddd with 24 atoms per unit cell. Basov et al 14) observed that the Al 2 Ru is infrared active, indicating the presence of a gap. Mandrus et al 15) reported the temperature dependence of the thermoelectric properties of the Al 2 Ru.…”

Section: Introductionmentioning

confidence: 99%

Thermoelectric Properties of Binary Semiconducting Intermetallic Compounds Al<SUB>2</SUB>Ru and Ga<SUB>2</SUB>Ru Synthesized by Spark Plasma Sintering Process

et al. 2010

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The authors report the electrical and thermal transport properties of binary semiconducting intermetallic Al 2 Ru and Ga 2 Ru compounds from 373 to 973 K. We synthesized sintered pellets of Al 2 Ru and Ga 2 Ru by the spark plasma sintering (SPS) method, resulted in a removal of small amount of a secondary phase and of cracks. The maximum Seebeck coefficient of Al 2 Ru and Ga 2 Ru shows a large positive value of 200 mV/K and 360 mV/K, respectively. In particular, a large power factor $2:8 mW/m-K 2 was obtained at 773 K in Ga 2 Ru compound. The dimensionless figures of merit ZT of sintered Al 2 Ru and Ga 2 Ru samples monotonically increase with increasing temperature and reach a maximum value of 0.20 and 0.45 at about 873 K and 773 K, respectively.

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“…[30][31][32][33] A universal experimental relation ϳ␥ Ϫ1/2 , discovered independently by Mizutani 32 and Rapp 33 for many i alloys, is indicative of the minimum of the DOS(E F ) in these alloys. The results of NMR, 34 -37 optical conductivity, [38][39][40][41][42][43] and photoconductivity 44 experiments were interpreted in terms of the pseudogap in the DOS(E F ) in the i alloys.…”

Section: Introductionmentioning

confidence: 99%

Absence of fine structure in the photoemission spectrum of the icosahedral Al-Pd-Mn quasicrystal

et al. 2001

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Absence of fine structure in the photoemission spectrum of the icosahedral Al-Pd-Mn quasicrystal AbstractThe results of the low-temperature ultrahigh-energy-resolution photoemission studies of a single-grain icosahedral alloy Al 70 Pd 21.5 Mn 8.5 have been presented. The existence of the theoretically predicted pseudogap in the density of states at the Fermi energy has been confirmed. No evidence of the theoretically predicted spikiness of the density of states could be observed. It has been suggested that the failure to detect the predicted spikiness of the density of states in icosahedral quasicrystals is consistent with the results of Zijlstra and Janssen [Europhys. Lett. 52, 578 (2000)] who showed that the spikiness occurs only in lowerorder periodic approximants to icosahedral quasicrystals, but does not survive in the quasiperiodic limit. Disciplines Condensed Matter Physics | Metallurgy CommentsThis article is from Physical Review B 64 (2001) The results of the low-temperature ultrahigh-energy-resolution photoemission studies of a single-grain icosahedral alloy Al 70 Pd 21.5 Mn 8.5 have been presented. The existence of the theoretically predicted pseudogap in the density of states at the Fermi energy has been confirmed. No evidence of the theoretically predicted spikiness of the density of states could be observed. It has been suggested that the failure to detect the predicted spikiness of the density of states in icosahedral quasicrystals is consistent with the results of Zijlstra and Janssen ͓Europhys. Lett. 52, 578 ͑2000͔͒ who showed that the spikiness occurs only in lower-order periodic approximants to icosahedral quasicrystals, but does not survive in the quasiperiodic limit.

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Optical Conductivity of Insulating Al-Based Alloys: Comparison of Quasiperiodic and Periodic Systems

Cited by 92 publications

References 17 publications

Anomalous effective charges and far-IR optical absorption ofAl2Ru from first principles

Anomalous effective charges and far-IR optical absorption ofAl2Ru from first principles

Thermoelectric Properties of Binary Semiconducting Intermetallic Compounds Al<SUB>2</SUB>Ru and Ga<SUB>2</SUB>Ru Synthesized by Spark Plasma Sintering Process

Absence of fine structure in the photoemission spectrum of the icosahedral Al-Pd-Mn quasicrystal

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