First-principles investigation of structural, electronic, and thermoelectric properties of n- and p-type Mg2Si

Hirayama, Naomi; Iida, Tsutomu; Morioka, Shunsuke; Sakamoto, Mariko; Nishio, K.; Kogo, Yasuo; Takanashi, Yoshifumi; Hamada, Nobuyuki

doi:10.1557/jmr.2015.206

Cited by 16 publications

(12 citation statements)

References 28 publications

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“…Formation energies ΔE(x) and DOS values of (a) B-and (b) Ga-doped Mg 2 Si for Mg (circles), Si (triangles), and 4b (crosses) sites. Here, the ΔE(x) for B-doped systems are similar to the calculation results obtained under different condition [25]. According to the obtained formation energies, both impurities tend to substitute Si atoms.…”

Section: Alkaline Metals At Mg-sitesupporting

confidence: 84%

“…Formation energies and DOS values of (a) Li-, (b) Na-, and (c) K-doped Mg 2 Si determined for Mg (circles), Si (triangles), and 4b (crosses) sites. Here, the results of ΔE(x) for Na-doped systems are almost identical to ones obtained in our previous study [25] where the different calculation conditions were used. The obtained results show that Mg and 4b sites are the two preferred sites for these impurities.…”

Section: Site Stability Of Conventional P-type Ag Dopantsupporting

confidence: 84%

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Substitutional and interstitial impurity p-type doping of thermoelectric Mg₂Si: a theoretical study

Hirayama

Iida

Sakamoto

et al. 2019

Science and Technology of Advanced Materials

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The narrow-gap magnesium silicide semiconductor Mg 2 Si is a promising mid-temperature (600-900 K) thermoelectric material. It intrinsically possesses n-type conductivity, and n-type dopants are generally used for improving its thermoelectric performance; however, the synthesis of p-type Mg 2 Si is relatively difficult. In this work, the hole doping of Mg 2 Si with various impurity atoms is investigated by performing first principles calculations. It is found that the Ag-doped systems exhibit comparable formation energies ΔE calculated for different impurity sites (Mg, Si, and interstitial 4b ones), which may explain the experimental instability of their p-type conductivity. A similar phenomenon is observed for the systems incorporating alkali metals (Li, Na, and K) since their ΔE values determined for Mg (p-type) and 4b (n-type) sites are very close. Among boron group elements (Ga and B), Ga is found to be favorable for hole doping because it exhibits relatively small ΔE values for Si (p-type) sites. Furthermore, the interstitial insertion of Cl and F atoms into the crystal lattice leads to hole doping because of their high electronegativity.

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Section: Alkaline Metals At Mg-sitesupporting

confidence: 84%

Section: Site Stability Of Conventional P-type Ag Dopantsupporting

confidence: 84%

Substitutional and interstitial impurity p-type doping of thermoelectric Mg₂Si: a theoretical study

Hirayama

Iida

Sakamoto

et al. 2019

Science and Technology of Advanced Materials

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“…Such decrease in the lattice constant has been reported theoretically for an Al-doped Mg 2 Si system. 25) Thus, we can assume that some of the Al in the xAl/Mg 2 Si samples was used for the partial substitution in the Mg 2 Si matrix, and that the substitution amount increased up to x = 0.75.…”

Section: Resultsmentioning

confidence: 99%

“…It has been predicted that the doped Al substitutes for the Mg site, leading to electron carrier doping. 7,25) Additionally, Al metal possesses a high electron carrier density of 1.89 © 10 23 cm ¹3 . 24) Therefore, it is expected that both the Al-substitution in Mg 2 Si and incorporation of the Al phase in the Mg 2 Si matrix increase the electrical conductivity of the xAl/Mg 2 Si samples.…”

Section: Resultsmentioning

confidence: 99%

Fabrication and Thermoelectric Properties of Al/Mg2Si Composite Materials

et al. 2018

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Mg 2 Si has attracted interest as a potential thermoelectric material that can convert waste heat into electricity. To improve thermoelectric performance of Mg 2 Si, Al/Mg 2 Si composite materials with nominal composition of xAl/Mg 2 Si (x = 0.25, 0.5, 0.75, 1.0, or 1.5) were fabricated, i.e., an Al metal phase was introduced to an Mg 2 Si matrix. Reflecting an increase in the electrical conductivity and a decrease in the Seebeck coefficient with increasing x, the power factor was successfully enhanced by the incorporation of the Al phase. The increase in electrical conductivity was discussed in terms of electron carrier density and carrier mobility.

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“…Valuable contributions [8][9][10][11][12][13][14] are emerging from the scientific community applying density functional theory (DFT) for prediction of Seebeck coefficient. Unfortunately, underestimation of band gap is a well-known flaw of DFT, which usually results [15][16][17][18] in overestimating bipolar conduction and, thus, underestimating the Seebeck coefficient at high temperatures and low doping levels.…”

Section: Introductionmentioning

confidence: 99%

Prediction of seebeck coefficient for compounds without restriction to fixed stoichiometry: A machine learning approach

Furmanchuk

Saal²,

Doak³

et al. 2017

J Comput Chem

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The regression model-based tool is developed for predicting the Seebeck coefficient of crystalline materials in the temperature range from 300 K to 1000 K. The tool accounts for the single crystal versus polycrystalline nature of the compound, the production method, and properties of the constituent elements in the chemical formula. We introduce new descriptive features of crystalline materials relevant for the prediction the Seebeck coefficient. To address off-stoichiometry in materials, the predictive tool is trained on a mix of stoichiometric and nonstoichiometric materials. The tool is implemented into a web application (http://info.eecs.northwestern.edu/SeebeckCoefficientPredictor) to assist field scientists in the discovery of novel thermoelectric materials. © 2017 Wiley Periodicals, Inc.

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First-principles investigation of structural, electronic, and thermoelectric properties of n- and p-type Mg₂Si

Abstract: Abstract

Cited by 16 publications

References 28 publications

Substitutional and interstitial impurity p-type doping of thermoelectric Mg₂Si: a theoretical study

Substitutional and interstitial impurity p-type doping of thermoelectric Mg₂Si: a theoretical study

Fabrication and Thermoelectric Properties of Al/Mg<sub>2</sub>Si Composite Materials

Prediction of seebeck coefficient for compounds without restriction to fixed stoichiometry: A machine learning approach

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First-principles investigation of structural, electronic, and thermoelectric properties of n- and p-type Mg2Si

Abstract: Abstract

Cited by 16 publications

References 28 publications

Substitutional and interstitial impurity p-type doping of thermoelectric Mg2Si: a theoretical study

Substitutional and interstitial impurity p-type doping of thermoelectric Mg2Si: a theoretical study

Fabrication and Thermoelectric Properties of Al/Mg<sub>2</sub>Si Composite Materials

Prediction of seebeck coefficient for compounds without restriction to fixed stoichiometry: A machine learning approach

Contact Info

Product

Resources

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First-principles investigation of structural, electronic, and thermoelectric properties of n- and p-type Mg₂Si

Substitutional and interstitial impurity p-type doping of thermoelectric Mg₂Si: a theoretical study

Substitutional and interstitial impurity p-type doping of thermoelectric Mg₂Si: a theoretical study