Some physical properties of the PbTe-MgTe alloy system

Crocker, A.J.; Sealy, B.J.

doi:10.1016/s0022-3697(72)80294-4

Cited by 29 publications

(30 citation statements)

References 14 publications

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“…It is shown that alloying PbTe with MnTe and MgTe has undistinguishable Seebeck coefficient and Hall mobility, suggesting a similar effect on modifying the band structure. 5,[32][33][34][35][36][37][38] This can be understood by the undistinguishable alloy composition-dependent direct optical band gap (E g ) in these two alloy systems as shown in Figure 2. This is also consistent with the band-structure calculation in Pb 1 Àx Mn x Te.…”

Section: Resultsmentioning

confidence: 99%

“…31 Additionally, alloys of PbTe with isovalent elements can also adjust the energy offset between the two-valence bands leading to similar band-tuning effects. 3,5,29,[32][33][34][35][36][37][38][39][40] In the case of Pb 1 Àx Mg x Te, the roomtemperature band gap increases with increasing Mg content, meaning the energy of the light valence band is reduced to achieve an effective alignment with the heavy band even at room temperature. 5,[33][34][35] This is an opposite effect to the PbTe 1 Àx Se x alloys, which has a slightly lower band gap that produces band alignment at higher temperatures.…”

Section: Introductionmentioning

confidence: 99%

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Thermopower enhancement in Pb1−xMnxTe alloys and its effect on thermoelectric efficiency

et al. 2012

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Thermopower enhancement in Pb1−xMnxTe alloys and its effect on thermoelectric efficiency

et al. 2012

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“…Many experimental works were performed with alloying to adjust the convergence temperature to desired range. The band structure modifications of PbTe-based materials through isovalent substitutions by Mn, 58,59 IIB, 60 and IIA elements 61 were originally studied before 1980s, [62][63][64] and have been revisited with intensive investigation for TE applications. Compared to lead chalcogenides, the strategy of valley convergence through alloying plays a more important role in the zT enhancement for SnTe, since the room temperature energy offset between L and Σ valleys for SnTe is much higher (~0.3 eV for SnTe,~0.1 eV for PbTe).…”

Section: Valley Degeneracymentioning

confidence: 99%

Valleytronics in thermoelectric materials

et al. 2018

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The central theme of valleytronics lies in the manipulation of valley degree of freedom for certain materials to fulfill specific application needs. While thermoelectric (TE) materials rely on carriers as working medium to absorb heat and generate power, their performance is intrinsically constrained by the energy valleys to which the carriers reside. Therefore, valleytronics can be extended to the TE field to include strategies for enhancing TE performance by engineering band structures. This review focuses on the recent progress in TE materials from the perspective of valleytronics, which includes three valley parameters (valley degeneracy, valley distortion, and valley anisotropy) and their influencing factors. The underlying physical mechanisms are discussed and related strategies that enable effective tuning of valley structures for better TE performance are presented and highlighted. It is shown that valleytronics could be a powerful tool in searching for promising TE materials, understanding complex mechanisms of carrier transport, and optimizing TE performance.npj Quantum Materials (2018) 3:9 ; doi:10.1038/s41535-018-0083-6 INTRODUCTIONThe demand for renewable energy harvesting has been growing because of the limited fossil fuels and increasing worldwide energy consumption. Thermoelectric (TE) materials, which have the capability of converting heat directly into electricity under a temperature gradient, have been regarded as an alternative option to alleviate energy shortage.1 Though TE devices have already been applied in deep space exploration and solid state cooling, 2,3 the relatively low energy conversion efficiency limits their wide commercialization, 4 which is mainly constrained by the performance of TE materials as characterized by the dimensionless figure of merit, zT = α 2 σT/(κ e + κ L ), where α is the Seebeck coefficient, σ is the electrical conductivity, κ e and κ L are, respectively, the electronic and lattice contributions to the total thermal conductivity κ, and T is the absolute temperature.5 Since all three physical properties (α, σ, and κ) are carrier concentration dependent, zT could reach its maximum value at an optimized carrier concentration. zT max is determined by a combination of intrinsic physical parameters as well as the temperature, all of which integrated into a term called the TE quality factor, B. Higher quality factor B leads to higher zT max at a fixed temperature. With a single parabolic band model in the nondegenerate limit, B could be expressed as:

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“…For example alloys with PbSe, [ 12 ] MgTe, [24][25][26] and (Zn, Cd, Hg)Te [ 27 ] increase the energy separation of both L and Σ bands with respect to the C band. Alloying with MgTe has an exceptional infl uence on the band structure ( Figure 2 a) up to the solubility limit ( x ≈ 0.06 in Mg x Pb 1-x Te for T > 525 K), [ 25 , 27 ] as can be qualitatively explained by the much wider bandgap ( ≈ 3.5 eV) of MgTe [ 11 ] than PbTe ( ≈ 0.3 eV at 300 K).…”

Section: Doi: 101002/adma201103153mentioning

confidence: 99%