Effects of Cu doping on thermoelectric properties of Al–Si–Ru semiconducting quasicrystalline approximant

Iwasaki, Yutaka; Kitahara, Koichi; Kimura, Kaoru

doi:10.1103/physrevmaterials.5.125401

Cited by 3 publications

(3 citation statements)

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“…Based on the study of these electronic rules, we have recently discovered a semiconducting 1/0 approximant in the ternary Al–Si–Ru system . We also found that this approximant is promising as a thermoelectric material for low-temperature waste-heat recovery . These results suggest that the realization of semiconducting quasicrystals will lead to a greater thermoelectric performance than conventional semimetallic quasicrystals.…”

Section: Introductionmentioning

confidence: 73%

“…11 We also found that this approximant is promising as a thermoelectric material for low-temperature waste-heat recovery. 28 These results suggest that the realization of semiconducting quasicrystals will lead to a greater thermoelectric performance than conventional semimetallic quasicrystals. The next step for understanding the electronic structure of semiconducting quasicrystals is to clarify the mechanism of forming a band gap on a semiconducting approximant with a higher degree of approximation, such as the 1/1 approximant.…”

Section: ■ Introductionmentioning

confidence: 94%

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Three-Center Bonds in an Al–Pd–Co Quasicrystalline Approximant: Wannier Function-Based Chemical Bonding Analysis

Iwasaki,

Kimura,

Kitahara

2023

J. Phys. Chem. C

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The relationship between the valence electronic state and crystal structure of aluminum−transition-metal quasicrystals and their approximants remains to be elucidated. The origin of the semiconducting band structure on the Katz−Gratias− Boudard-type 1/1 approximants has yet to be clarified. We calculated the electronic structure of an Al−Pd−Co 1/1 quasicrystalline approximant (Al 92 Pd 8 Co 28 per unit cell) using density functional theory and analyzed the approximant's valence orbital character by constructing maximally localized Wannier functions. Among the 304 Wannier functions constructed from the valence bands, 288 were localized around transition metal atoms and 12 were localized between two Co atoms. The other four functions were localized around the center of three-membered rings of Co atoms, which indicates the presence of three-center bonds in this approximant. This situation is an exception to the Yannello− Fredrickson and Kitahara's electron rules, which explain the valence electronic states of aluminum−transition metal approximants and their related intermetallic compound semiconductors considering only two-center bonds. In this study, these rules are expanded to consider three-center bonds, making it possible to explain the semiconducting origin. This work indicates that the electron rule considering three-center bonds can be applied to quasicrystals and other approximants that have triangle networks.

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Section: Introductionmentioning

confidence: 73%

Section: ■ Introductionmentioning

confidence: 94%

Three-Center Bonds in an Al–Pd–Co Quasicrystalline Approximant: Wannier Function-Based Chemical Bonding Analysis

Iwasaki,

Kimura,

Kitahara

2023

J. Phys. Chem. C

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“…To optimize ρ and k, specific microstructure, which includes various defects with desired properties, shape, size, dimensionality and etc., is usually formed via various approaches and ways of defect engineering [2][3][4][5]. Elemental doping is one of fruitful ways that is often applied to optimally tune the transport properties and, hence, enhance thermoelectric efficiency of material [6][7][8][9][10][11][12][13][14][15]. Dopant atoms can behave as donor or acceptor centres, resulting in reducing in ρ and enhancing in the electronic contribution to k. Besides, dopant atoms are effective scattering centres for electrons and phonons, resulting in enhancing in ρ and reducing in the phonon contribution to k, respectively.…”

Section: Introductionmentioning

confidence: 99%