Reduced lattice thermal conductivity in Bi-doped Mg2Si0.4Sn0.6

Gao, Peng; Lu, Xu; Berkun, Isil; Schmidt, Robert D.; Case, Eldon D.; Hogan, Timothy P.

doi:10.1063/1.4901178

Cited by 48 publications

(27 citation statements)

References 21 publications

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“…Along with the increased PF for n-type conduction, the maximum ZT value we calculated is 1.75 at µ=0.22 eV corresponding to carrier concentration of 5.57 × 10 20 cm −3 . This enhanced ZT is in agreement with previous experiments that reported values of 1.55 (773 K), 43 1.2 (850 K) 44 and 1.4 (800 K) 45 for Mg 2.08 Si 0.37 Sn 0.6 Bi 0.03 , Mg 2 Si 0.57 Sn 0.4 Bi 0.03 and Mg 2. 16 Si 0.388 Sn 0.582 Bi 0.03 , respectively.…”

Section: A Stability and Electronic Structuresupporting

confidence: 93%

Enhanced thermoelectric performance of Mg2Si1−xSnx codoped with Bi and Cr

2018

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Magnesium silicides are favorable thermoelectric materials considering resource abundance and cost. Chromium (Cr) doping in magnesium silicides has not yet been explored. Using first-principles calculations, we have studied the stability of Mg2Si with chromium (1.85, 3.7, 5.55 and 6.25%Cr) and tin (12.5 and 50%Sn). Three Mg2Si compounds doped with Sn, (Sn+Bi), and (Sn+Bi+Cr) are used to explain doping effects on thermoelectric performance. Notably, Cr behaves non-magnetically for ≤ 2%Cr, after which ferromagnetic ordering is favored (≤12.96%Cr), despite its elemental antiferromagnetic state. With alloying of Sn (70.4%), Mg2Si remains an indirect-bandgap semiconductor, but adding small amounts of Bi (3.7%) increases the carrier concentration such that electrons occupy conduction bands, making it a degenerate semiconductor. Mg2Si0.296Sn0.666Bi0.037 is found to give the highest thermoelectric figure of merit (ZT) and power factor (PF) at 700 K, i.e., 1.75 and 7.04 mW m −1 K −2 , respectively. Adding small %Cr decreases ZT and PF to 0.78 and 4.33 mW m −1 K −2 , respectively. Such a degradation in TE performance is attributed to two factors: (i) uniform doping acting as an electron acceptor, decreasing conduction, and (ii) the loss of low-lying conduction band degeneracy with doping, decreasing the Seebeck coefficients. A study of configurations of Cr doping suggests that Cr has a tendency to form clusters inside the lattice which play a crucial role in tuning the magnetic and TE performance of doped-Mg2Si compounds.

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Section: A Stability and Electronic Structuresupporting

confidence: 93%

Enhanced thermoelectric performance of Mg2Si1−xSnx codoped with Bi and Cr

2018

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“…A 400 keV beam of He 2+ ions and a detection angle of 107.5° was used for the detector. [14,15,16]. In addition to the Mg 2 Si phase, an elemental Mg phase is also observed, as indicated by the peaks at 36.59 o , 34.27 o and 32.15 o [17].…”

Section: Grazing Incidence X-ray Diffraction (Gixrd Rigaku Ultima IImentioning

confidence: 94%

Electrical transport characterization of Al and Sn doped Mg 2 Si thin films

Zhang

Zheng

Sun

et al. 2017

Journal of Alloys and Compounds

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Thin-film Mg 2 Si was deposited using radio frequency (RF) magnetron sputtering. Al and Sn were incorporated as n-type dopants using co-sputtering to tune the thin-film electrical properties. X-ray diffraction (XRD) analysis confirmed that the deposited films are polycrystalline Mg 2 Si. The Sn and Al doping concentrations were measured using Rutherford backscattering spectroscopy (RBS) and energy dispersive X-ray spectroscopy (EDS). The charge carrier concentration and the charge carrier type of the Mg 2 Si films were measured using a Hall bar structure. Hall measurements show that as the doping concentration increases, the carrier concentration of the Al-doped films increases, whereas the carrier concentration of the Sn-doped films decreases. Combined with the resistivity measurements, the mobility of the Al-doped

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“…The room temperature lattice thermal conductivity decreases as Mg excess increases in the range of 2.8 W•m -1 •K -1 to 2.5 W•m -1 •K -1 . It was reported that the bismuth interstitial can decrease the lattice thermal conductivity obviously in the Mg 2 (Si,Sn) ternary solid solution [8] . The decrease of the lattice thermal conductivity may be due to the Mg interstitials.…”

Section: Methodsmentioning

confidence: 98%

Thermoelectric Performance of Quaternary Mg2Si0.27Ge0.05-Sn0.65Sb0.03 Solid Solutions

Song

et al. 2018

Rare Metal Materials and Engineering

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Single-phased Mg2(1+x)Si0.27Ge0.05Sn0.65Sb0.03 (x=0.05, 0.08) quaternary solid solutions were prepared by B2O3 flux method followed by spark plasma sintering (SPS). The electrical conductivity, Seebeck coefficient and thermal conductivity were measured from 300 to 800 K. The results show that the electrical conductivity increases while the Seebeck coefficient decreases with temperature rising for these samples. The lattice thermal conductivities of all the samples are higher than the calculated value using the Abeles model. A maximum ZT of 1.0 at 800 K is obtained in the sample with x=0.08.

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Reduced lattice thermal conductivity in Bi-doped Mg2Si0.4Sn0.6

Cited by 48 publications

References 21 publications

Enhanced thermoelectric performance of Mg2Si1−xSnx codoped with Bi and Cr

Enhanced thermoelectric performance of Mg2Si1−xSnx codoped with Bi and Cr

Electrical transport characterization of Al and Sn doped Mg 2 Si thin films

Thermoelectric Performance of Quaternary Mg2Si0.27Ge0.05-Sn0.65Sb0.03 Solid Solutions

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