Liquid semiconductors and thermoelectric power generation: Mg-Sb

Verbrugge, Dawn M; Zytveld, J B Van

doi:10.1088/0022-3727/26/10/026

Cited by 4 publications

(3 citation statements)

References 5 publications

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“…The magnesium antimonide compound has played an important role in various functional materials (thermoelectricity [1], lithium battery [2], photoconduction [3], hydrogen transmitting [4], etc) and structural materials [5]. Recently, Mg 3 Sb 2 was studied [1] as a candidate thermoelectric material because of its high Seebeck coefficient (∼600 µV K −1 at 300 K) and low thermal conductivity (about 1 W m −1 K −1 at 300 K) [6,7]. 1 Author to whom any correspondence should be addressed.…”

Section: Introductionmentioning

confidence: 99%

Electrical and thermoelectric properties of nanocrystal substitutional semiconductor alloys Mg₃(Bi_xSb_1−x)₂prepared by mechanical alloying

Xin¹,

Qin²

2006

J. Phys. D: Appl. Phys.

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Nanocrystal substitutional semiconductor alloys Mg3(BixSb1−x)2 (nano-Mg3(BixSb1−x)2) with a mean grain size of ∼30 nm were prepared by mechanical alloying plus hot-pressing, and their dc electrical and thermoelectric properties were investigated from room temperature down to 20 K. The results indicated that lattice parameters a and c of nano-Mg3(BixSb1−x)2 increased linearly with increasing Bi content x, in agreement with Vegard's law. The dc resistivity ρ of nano-Mg3(BixSb1−x)2 decreased monotonically with increasing x, and a drop of over five orders of magnitude was reached at 300 K when x increased from 0 to 1. Moreover, the temperature behaviour of the resistivity of nano-Mg3(BixSb1−x)2 changed sensitively with x, and a transition from the semiconducting state (i.e. dρ/dT < 0) to the metallic state (dρ/dT > 0) occurred between x = 0.7 and 0.8. Meanwhile, this transition was verified by the measurements of the temperature behaviour of the Seebeck coefficient S of nano-Mg3(Bi1−xSbx)2 with different x. In addition, Mott's ρ ∝ T−1/4 law was observed at lower temperature regimes for the nano-Mg3(BixSb1−x)2 (x ≠ 0), suggesting the occurrence of hopping conduction. Although experiments showed that the Seebeck coefficient of nano-Mg3(Bi1−xSbx)2 decreased monotonically with x, their thermoelectric power factors PF changed non-monotonically, and a maximum PF of 1.4 µW cm−1 K−2 was achieved at room temperature for x = ∼0.8, which was more than three orders magnitude greater than that of monolithic Mg3Sb2.

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Section: Introductionmentioning

confidence: 99%

Electrical and thermoelectric properties of nanocrystal substitutional semiconductor alloys Mg₃(Bi_xSb_1−x)₂prepared by mechanical alloying

Xin¹,

Qin²

2006

J. Phys. D: Appl. Phys.

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“…This is remarkable as so drastic a metal-nonmetal transition in this direction (the solid is a metal and the liquid a semiconductor) had not been observed before (indeed negative changes in the conductivity upon melting occur for most NFE metals and alloys and, e.g., for Te-chalcogenide alloys, but the magnitude of the jump is much smaller in these cases). Also liquid Mg 3 Sb 2 is a semiconductor [14,15]. Plotted as a function of composition the resistivities of liquid Mg-Bi and Mg-Sb exhibit extremely sharp peaks at the octet composition.…”

Section: Introductionmentioning

confidence: 99%

First-principles molecular dynamics simulation of liquid

Wijs

Pastore

Selloni

et al. 1996

J. Phys.: Condens. Matter

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The liquid Mg-Bi system exhibits strong compound formation at the 'octet' composition (Mg 3 Bi 2 ). We present results of first-principles molecular dynamics simulations of this alloy system at different compositions: the pure Mg and Bi liquid components, the stoichiometric liquid, and a Mg-rich composition (Mg 62 Bi 28 ). For the pure liquids, our results are in excellent agreement with experimental diffraction data. For Mg 3 Bi 2 , a significant modification of the characteristics of the local ordering is found w.r.t. the crystalline α-phase: the ordering in the liquid is much more ionic. This structural modification is consistent with the structure of the superionic β-phase, that was reported recently by Barnes et al 1994 J. Phys.: Condens. Matter 6 L467. Our simulations cannot reproduce the 'reverse' metal-nonmetal transition observed upon melting, the computed conductivity being much larger than found in experiments. Instead, for the Mg-rich Mg 62 Bi 28 alloy, the calculated conductivity approaches closely to the experimental value.

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“…Mg 3 Sb 2 forms a hexagonal crystal with anti-La 2 O 3 type structure, which suggests an ionic compound [5,11]. The preparation of polycrystalline Mg 3 Sb 2 is difficult due to the fact that composition changes often occur because of high vapour pressure of magnesium at high temperatures [12]. Especially, to our knowledge, the fabrication of nanocrystalline Mg 3 Sb 2 and its correlative properties have seldom been reported so far.…”

Section: Introductionmentioning

confidence: 99%

Temperature dependence of electrical resistivity for nanocrystalline Mg_3+xSb₂prepared by mechanical alloying

Xin¹,

Qin²,

Zhu³

et al. 2006

J. Phys. D: Appl. Phys.

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The temperature dependence of dc electrical resistivity of nanocrystalline Mg3+xSb2 (nano-Mg3+xSb2) (mean grain sizes d ∼ 30 nm), prepared by mechanical alloying plus hot-pressing (HP), was investigated below room temperature. The results indicate that composition deviation x from stoichiometry has a strong influence on the temperature dependence of the resistivity. For the specimens with smaller absolute composition deviation |x|, their resistivity ρ increased exponentially with decreasing temperature, i.e. lnρ ∝ 1/T in the whole temperature range investigated. However, for the specimens with very large |x| or those with a large |x| after HP for a longer time, the relationship ln ρ ∝ 1/T existed only in the high temperature regime; at low temperatures Mott's ln ρ ∝ T−1/4 law was observed in these specimens, indicating that large compositional deviations produced strong random potential, which led to the formation of considerable localized states. By fitting the experimental data to Mott's T−1/4 law, we estimated the density of localized states N(EF) at the Fermi level, which was found to increase with increasing composition deviation |x| in nano-Mg3+xSb2.

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Liquid semiconductors and thermoelectric power generation: Mg-Sb

Cited by 4 publications

References 5 publications

Electrical and thermoelectric properties of nanocrystal substitutional semiconductor alloys Mg₃(Bi_xSb_1−x)₂prepared by mechanical alloying

Electrical and thermoelectric properties of nanocrystal substitutional semiconductor alloys Mg₃(Bi_xSb_1−x)₂prepared by mechanical alloying

First-principles molecular dynamics simulation of liquid

Temperature dependence of electrical resistivity for nanocrystalline Mg_3+xSb₂prepared by mechanical alloying

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Liquid semiconductors and thermoelectric power generation: Mg-Sb

Cited by 4 publications

References 5 publications

Electrical and thermoelectric properties of nanocrystal substitutional semiconductor alloys Mg3(BixSb1−x)2prepared by mechanical alloying

Electrical and thermoelectric properties of nanocrystal substitutional semiconductor alloys Mg3(BixSb1−x)2prepared by mechanical alloying

First-principles molecular dynamics simulation of liquid

Temperature dependence of electrical resistivity for nanocrystalline Mg3+xSb2prepared by mechanical alloying

Contact Info

Product

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Electrical and thermoelectric properties of nanocrystal substitutional semiconductor alloys Mg₃(Bi_xSb_1−x)₂prepared by mechanical alloying

Electrical and thermoelectric properties of nanocrystal substitutional semiconductor alloys Mg₃(Bi_xSb_1−x)₂prepared by mechanical alloying

Temperature dependence of electrical resistivity for nanocrystalline Mg_3+xSb₂prepared by mechanical alloying