Sharp Feature in the Pseudogap of Quasicrystals Detected by NMR

Tang, Xiangwei; Hill, E. A.; Wonnell, S. K.; Poon, S. J.; Wu, Yue

doi:10.1103/physrevlett.79.1070

Cited by 50 publications

(24 citation statements)

References 22 publications

(31 reference statements)

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“…5 However we found no evidence for a temperature dependence to K m , as has been found in some systems 37,38 for which narrow pseudogap features dominate near ε F . Thus from this standpoint Fe 2 Al 5 behaves as an ordinary metal.…”

Section: Discussioncontrasting

confidence: 43%

Dilute magnetism and vibrational entropy inFe2Al5

et al. 2010

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Fe2Al5 contains a Fe-Al matrix through which are threaded disordered one-dimensional chains of overlapping Al sites. We report magnetic, NMR, and specific heat measurements addressing its magnetic and vibrational properties. The Curie-type susceptibility is found to be due to dilute moments, likely due to wrong-site Fe atoms.27 Al NMR shift and spin-lattice relaxation measurements confirm these to be indirectly coupled through an RKKY-type interaction. Specific heat results indicate a large density of low-energy vibrational modes. These excitations generate a linear-T contribution to the specific heat, which however freezes out below about 10 K. These results are attributed to the presence of anharmonic vibrational modes associated with the disordered structural chains.

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Section: Discussioncontrasting

confidence: 43%

Dilute magnetism and vibrational entropy inFe2Al5

et al. 2010

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“…It is suggested that spikes could be artifacts of the calculation 26,27 or only specific to small periodic approximants 24,28,29 ͑APP's͒. On the other hand, there is experimental evidence 30,31 for significant spectral structures around the Fermi energy down to a few 10 meV. Measurements 9,10,32,33 of the temperature-dependent conductivity and the thermopower indicate also the presence of narrow pseudogaps ͑width ϳ0.1-0.2 eV͒ in the spectral conductivity.…”

Section: Introductionmentioning

confidence: 96%

Analytical expressions for the transport coefficients of icosahedral quasicrystals

2003

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We investigate by analytical means the electronic transport properties of approximants and quasicrystals. The spectral resistivity is modeled by Lorentz functions in agreement with realistic ab initio calculations ͑linear muffin-tin orbital basis, Kubo-Greenwood formula͒ for low-order approximants. The analytical expressions for the transport coefficients compare well with both numerical calculations and experiments. Thus, the temperature-dependent conductivity, thermopower, electronic thermal conductivity, and Lorenz number of certain approximants and quasicrystals can be consistently explained.

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“…1͒ agrees well with the experimental results obtained from tunneling and point contact spectroscopy measurements, where the presence of a dip feature of small width ͑20-60 meV͒, superimposed onto a broad ͑0.5-1 eV͒ asymmetric pseudogap, has been reported. 23,[31][32][33] Thus, Eq. ͑2͒ satisfactorily describes the electronic structure of these alloys in terms of a wide Lorentzian peak ͑related to the Fermi surface-Brillouin zone interaction͒ plus a narrow Lorentzian peak ͑related to sp-d hybridization effects͒.…”

Section: ͑2͒mentioning

confidence: 99%

Optimizing the thermoelectric efficiency of icosahedral quasicrystals and related complex alloys

Maciá

2009

Phys. Rev. B

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In this work we analyze the potential role of quasicrystals and related alloys in thermoelectric material research. Relatively large figure of merit values are expected for those samples exhibiting two properly located narrow features in the density of states close to the Fermi level. It is expected that optimized quasicrystals will perform better at relatively low temperatures, whereas the ZT curve of complex metallic alloys reaches its maximum at high temperatures. Among state-of-the-art quasicrystals most promising samples for thermoelectric applications are found in the AlPd͑Mn,Re͒ system. Quasicrystalline and related approximants in the ScMgCuGa and CaAuIn systems, synthesized on the basis of pseudogap tuning concepts, appear as promising candidates as well.

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Sharp Feature in the Pseudogap of Quasicrystals Detected by NMR

Cited by 50 publications

References 22 publications

Dilute magnetism and vibrational entropy inFe2Al5

Dilute magnetism and vibrational entropy inFe2Al5

Analytical expressions for the transport coefficients of icosahedral quasicrystals

Optimizing the thermoelectric efficiency of icosahedral quasicrystals and related complex alloys

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