Science China Materials

, Volume 62, Issue 3, pp 379–388 | Cite as

Promising cubic MnGeTe2 thermoelectrics

  • Binqiang Zhou (周斌强)
  • Wen Li (李文)Email author
  • Xiao Wang (王晓)
  • Juan Li (李娟)
  • Liangtao Zheng (郑良涛)
  • Bo Gao (高博)
  • Xinyue Zhang (张馨月)
  • Yanzhong Pei (裴艳中)Email author


Semiconducting cubic group IV monotellurides, including PbTe and SnTe, have historically led most of the advancements in thermoelectrics. Recently, noncubic ones such as GeTe and MnTe have also shown to be promising, which motivates the current work focusing on the thermoelectric properties of MnGeTe2, a derivative compound of noncubic GeTe and MnTe but crystalizing in a cubic structure. This compound intrinsically comes with a carrier concentration as high as ~3.6×1021 cm−3, indicating the existence of highconcentration cation vacancies due to Ge-precipitation. This intrinsic carrier concentration is much higher than that needed for thermoelectric applications but can be successfully decreased to ~9×1020 cm−3 for MnGe0.9Bi0.1Te2 at room temperature. Such a broad carrier concentration not only offers a full assessment of its electronic transport properties according to a single parabolic band model with acoustic scattering, but also enables an optimization for thermoelectric power factor. The low lattice thermal conductivity of ~1.2 W m−1 K−1 or lower in the entire temperature range, can be understood by the highly disordered cations and cation vacancies. A peak zT approaching 1.0 at 850 K was achieved in materials at an optimal carrier concentration of ~9×1020 cm−3, an isotropic cubic structure as well as a Vickers hardness of >200 HV, strongly indicating MnGeTe2 as a promising thermoelectric material.


thermoelectric MnGeTe2 zT SPB model 



具有立方结构的IV族碲化物半导体(PbTe和SnTe)已经引领了热电领域的诸多革新. 近年来, 非立方相化合物GeTe与MnTe也表现出 很好的热电前景. 基于此, 本文对GeTe与MnTe的衍生化合物(MnGeTe2)的热电性能进行了探究. 在本工作中, 本征态MnGeTe2因单质锗的 析出而存在高浓度的阳离子空位, 载流子浓度高达~3.6×1021 cm−3, 远高于热电应用所需, 通过Bi的掺杂可使得载流子显著降低(室温下 MnGe0.9Bi0.1Te2载流子约为~9×1020 cm−3). 在这样大的载流子浓度范围内, 一方面可以基于声学声子散射机制下的单抛物带模型, 实现对 载流子输运性质进行全面的评估; 另一方面还可以实现热电功率因子的优化. 此外, 由于材料中存在高度无序的阳离子和阳离子空位, 可 在测试温度范围内获得1.2 W m−1 K−1甚至更低的晶格热导率. 当载流子浓度达到优化值~9×1020 cm−3时, 在850 K各向同性的立方相下可获 得接近1.0的zT值以及高于200 HV的维氏硬度值, 进一步证实MnGeTe2是一个很有前景的热电材料.



This work is supported by the National Natural Science Foundation of China (11474219 and 51772215), the National Key Research and Development Program of China (2018YFB0703600), the Fundamental Research Funds for Science and Technology Innovation Plan of Shanghai (18JC1414600), the Fok Ying Tung Education Foundation (20170072210001) and “Shu Guang” Project Supported by Shanghai Municipal Education Commission and Shanghai Education Development Foundation.


  1. 1.
    Tan G, Shi F, Hao S, et al. Codoping in SnTe: enhancement of thermoelectric performance through synergy of resonance levels and band convergence. J Am Chem Soc, 2015, 137: 5100–5112CrossRefGoogle Scholar
  2. 2.
    Snyder GJ, Toberer ES. Complex thermoelectric materials. Nat Mater, 2008, 7: 105–114CrossRefGoogle Scholar
  3. 3.
    Chen Z, Zhang X, Pei Y. Manipulation of phonon transport in thermoelectrics. Adv Mater, 2018, 30: 1705617CrossRefGoogle Scholar
  4. 4.
    Morelli DT, Jovovic V, Heremans JP. Intrinsically minimal thermal conductivity in cubic I−V−VI2 semiconductors. Phys Rev Lett, 2008, 101: 035901CrossRefGoogle Scholar
  5. 5.
    Delaire O, Ma J, Marty K, et al. Giant anharmonic phonon scattering in PbTe. Nat Mater, 2011, 10: 614–619CrossRefGoogle Scholar
  6. 6.
    Lin S, Li W, Li S, et al. High thermoelectric performance of Ag9GaSe6 enabled by low cutoff frequency of acoustic phonons. Joule, 2017, 1: 816–830CrossRefGoogle Scholar
  7. 7.
    Li W, Lin S, Weiss M, et al. Crystal structure induced ultralow lattice thermal conductivity in thermoelectric Ag9AlSe6. Adv Energy Mater, 2018, 8: 1800030CrossRefGoogle Scholar
  8. 8.
    Li W, Lin S, Ge B, et al. Low sound velocity contributing to the high thermoelectric performance of Ag8SnSe6. Adv Sci, 2016, 3: 1600196CrossRefGoogle Scholar
  9. 9.
    Chen Z, Jian Z, Li W, et al. Lattice dislocations enhancing thermoelectric PbTe in addition to band convergence. Adv Mater, 2017, 29: 1606768CrossRefGoogle Scholar
  10. 10.
    Kim SI, Lee KH, Mun HA, et al. Dense dislocation arrays embedded in grain boundaries for high-performance bulk thermoelectrics. Science, 2015, 348: 109–114CrossRefGoogle Scholar
  11. 11.
    Chen Z, Ge B, Li W, et al. Vacancy-induced dislocations within grains for high-performance PbSe thermoelectrics. Nat Commun, 2017, 8: 13828CrossRefGoogle Scholar
  12. 12.
    Hsu KF, Loo S, Guo F, et al. Cubic AgPbmSbTe2+m: bulk thermoelectric materials with high figure of merit. Science, 2004, 303: 818–821CrossRefGoogle Scholar
  13. 13.
    Biswas K, He J, Blum ID, et al. High-performance bulk thermoelectrics with all-scale hierarchical architectures. Nature, 2012, 489: 414–418CrossRefGoogle Scholar
  14. 14.
    Poudel B, Hao Q, Ma Y, et al. High-thermoelectric performance of nanostructured bismuth antimony telluride bulk alloys. Science, 2008, 320: 634–638CrossRefGoogle Scholar
  15. 15.
    Ioffe AF, Ioffe AV. Thermal conductivity of solid solutions. Soviet Physics Solid State, 1960, 2(5): 719–728Google Scholar
  16. 16.
    Pei Y, Zheng L, Li W, et al. Interstitial point defect scattering contributing to high thermoelectric performance in SnTe. Adv Electron Mater, 2016, 2: 1600019CrossRefGoogle Scholar
  17. 17.
    Tan G, Zeier WG, Shi F, et al. High thermoelectric performance SnTe–In2Te3 solid solutions enabled by resonant levels and strong vacancy phonon scattering. Chem Mater, 2015, 27: 7801–7811CrossRefGoogle Scholar
  18. 18.
    Liu W, Tan X, Yin K, et al. Convergence of conduction bands as a means of enhancing thermoelectric performance of n-type Mg2Si1−xSnx solid solutions. Phys Rev Lett, 2012, 108: 166601CrossRefGoogle Scholar
  19. 19.
    Pei Y, Shi X, LaLonde A, et al. Convergence of electronic bands for high performance bulk thermoelectrics. Nature, 2011, 473: 66–69CrossRefGoogle Scholar
  20. 20.
    Heremans JP, Jovovic V, Toberer ES, et al. Enhancement of thermoelectric efficiency in PbTe by distortion of the electronic density of states. Science, 2008, 321: 554–557CrossRefGoogle Scholar
  21. 21.
    Kaidanov VI, Nemov SA, Ravich YI, et al. Influence of resonance states on the Hall-effect and electrical-conductivity of PbTe doped with both thallium and sodium simultaneously. Soviet Physics Semiconductors, 1983, 17(9): 1027–1030Google Scholar
  22. 22.
    Heremans JP, Wiendlocha B, Chamoire AM. Resonant levels in bulk thermoelectric semiconductors. Energy Environ Sci, 2012, 5: 5510–5530CrossRefGoogle Scholar
  23. 23.
    Bilc D, Mahanti SD, Quarez E, et al. Resonant states in the electronic structure of the high performance thermoelectrics AgPbmSbTe2+m: the role of Ag-Sb microstructures. Phys Rev Lett, 2004, 93: 146403CrossRefGoogle Scholar
  24. 24.
    Lin S, Li W, Chen Z, et al. Tellurium as a high-performance elemental thermoelectric. Nat Commun, 2016, 7: 10287CrossRefGoogle Scholar
  25. 25.
    Pei Y, Gibbs ZM, Gloskovskii A, et al. Optimum carrier concentration in n-Type PbTe thermoelectrics. Adv Energy Mater, 2014, 4: 1400486CrossRefGoogle Scholar
  26. 26.
    Pei Y, LaLonde AD, Heinz NA, et al. High thermoelectric figure of merit in PbTe alloys demonstrated in PbTe-CdTe. Adv Energy Mater, 2012, 2: 670–675CrossRefGoogle Scholar
  27. 27.
    Li W, Wu Y, Lin S, et al. Advances in environment-friendly SnTe thermoelectrics. ACS Energy Lett, 2017, 2: 2349–2355CrossRefGoogle Scholar
  28. 28.
    Al Rahal Al Orabi R, Mecholsky NA, Hwang J, et al. Band degeneracy, low thermal conductivity, and high thermoelectric figure of merit in SnTe–CaTe alloys. Chem Mater, 2016, 28: 376–384CrossRefGoogle Scholar
  29. 29.
    Banik A, Shenoy US, Anand S, et al. Mg alloying in SnTe facilitates valence band convergence and optimizes thermoelectric properties. Chem Mater, 2015, 27: 581–587CrossRefGoogle Scholar
  30. 30.
    Tan G, Zhao LD, Shi F, et al. High thermoelectric performance of p-Type SnTe via a synergistic band engineering and nanostructuring approach. J Am Chem Soc, 2014, 136: 7006–7017CrossRefGoogle Scholar
  31. 31.
    Zhang Q, Liao B, Lan Y, et al. High thermoelectric performance by resonant dopant indium in nanostructured SnTe. Proc Natl Acad Sci USA, 2013, 110: 13261–13266CrossRefGoogle Scholar
  32. 32.
    Li W, Zheng L, Ge B, et al. Promoting SnTe as an eco-friendly solution for p-PbTe thermoelectric via band convergence and interstitial defects. Adv Mater, 2016, 29: 1605887CrossRefGoogle Scholar
  33. 33.
    Tang J, Gao B, Lin S, et al. Manipulation of band structure and interstitial defects for improving thermoelectric SnTe. Adv Funct Mater, 2018, 24: 1803586CrossRefGoogle Scholar
  34. 34.
    Li J, Chen Z, Zhang X, et al. Electronic origin of the high thermoelectric performance of GeTe among the p-type group IV monotellurides. NPG Asia Mater, 2017, 9: e353–e353CrossRefGoogle Scholar
  35. 35.
    Li J, Zhang X, Chen Z, et al. Low-symmetry rhombohedral GeTe thermoelectrics. Joule, 2018, 2: 976–987CrossRefGoogle Scholar
  36. 36.
    Li J, Chen Z, Zhang X, et al. Simultaneous optimization of carrier concentration and alloy scattering for ultrahigh performance GeTe thermoelectrics. Adv Sci, 2017, 4: 1700341CrossRefGoogle Scholar
  37. 37.
    Hong M, Chen ZG, Yang L, et al. Realizing zT of 2.3 in Ge1−x−ySbxInyTe via reducing the phase-transition temperature and introducing resonant energy doping. Adv Mater, 2018, 30: 1705942CrossRefGoogle Scholar
  38. 38.
    Liu Z, Sun J, Mao J, et al. Phase-transition temperature suppression to achieve cubic GeTe and high thermoelectric performance by Bi and Mn codoping. Proc Natl Acad Sci USA, 2018, 115: 5332–5337CrossRefGoogle Scholar
  39. 39.
    Liu X, Zhu T, Wang H, et al. Low electron scattering potentials in high performance Mg2Si0.45Sn0.55 based thermoelectric solid solutions with band convergence. Adv Energy Mater, 2013, 3: 1238–1244CrossRefGoogle Scholar
  40. 40.
    Fu C, Zhu T, Pei Y, et al. High band degeneracy contributes to high thermoelectric performance in p-type half-Heusler compounds. Adv Energy Mater, 2014, 4: 1400600CrossRefGoogle Scholar
  41. 41.
    Ren Y, Yang J, Jiang Q, et al. Synergistic effect by Na doping and S substitution for high thermoelectric performance of p-type MnTe. J Mater Chem C, 2017, 5: 5076–5082CrossRefGoogle Scholar
  42. 42.
    Xu Y, Li W, Wang C, et al. Performance optimization and single parabolic band behavior of thermoelectric MnTe. J Mater Chem A, 2017, 5: 19143–19150CrossRefGoogle Scholar
  43. 43.
    Dudkin L, Kolomoets, N, Melikhova, A, et al. Influence of heattreatment on the structure and electrophysical properties of alloys GeTe-MnTe. Inorg Mater, 1979, 15: 166–169Google Scholar
  44. 44.
    Zhang Y, Wu L, Zhang J, et al. Eutectic microstructures and thermoelectric properties of MnTe-rich precipitates hardened PbTe. Acta Mater, 2016, 111: 202–209CrossRefGoogle Scholar
  45. 45.
    Fukuma Y, Asada H, Arifuku M, et al. Carrier-enhanced ferromagnetism in Ge1−xMnxTe. Appl Phys Lett, 2002, 80: 1013–1015CrossRefGoogle Scholar
  46. 46.
    Knoff W, Domukhovski V, Dybko K, et al. Ferromagnetic transition in Ge1−xMnxTe layers. Acta Phys Pol A, 2009, 116: 904–906CrossRefGoogle Scholar
  47. 47.
    Zhou Z, Uher C. Apparatus for Seebeck coefficient and electrical resistivity measurements of bulk thermoelectric materials at high temperature. Rev Sci Instruments, 2005, 76: 023901CrossRefGoogle Scholar
  48. 48.
    Hazan E, Madar N, Parag M, et al. Effective electronic mechanisms for optimizing the thermoelectric properties of GeTe-Rich alloys. Adv Electron Mater, 2015, 1: 1500228CrossRefGoogle Scholar
  49. 49.
    Fahrnbauer F, Souchay D, Wagner G, et al. High thermoelectric figure of merit values of germanium antimony tellurides with kinetically stable cobalt germanide precipitates. J Am Chem Soc, 2015, 137: 12633–12638CrossRefGoogle Scholar
  50. 50.
    Li J, Wu H, Wu D, et al. Extremely low thermal conductivity in thermoelectric Ge0.55Pb0.45Te solid solutions via Se substitution. Chem Mater, 2016, 28: 6367–6373CrossRefGoogle Scholar
  51. 51.
    Goldsmid HJ, Sharp JW. Estimation of the thermal band gap of a semiconductor from seebeck measurements. J Elec Materi, 1999, 28: 869–872CrossRefGoogle Scholar
  52. 52.
    Zheng Z, Su X, Deng R, et al. Rhombohedral to cubic conversion of GeTe via MnTe alloying leads to ultralow thermal conductivity, electronic band convergence, and high thermoelectric performance. J Am Chem Soc, 2018, 140: 2673–2686CrossRefGoogle Scholar
  53. 53.
    Ravich YI, Efimova BA, Smirnov IA. Semiconducting lead chalcogenides. Berlin: Plenum Press,1970CrossRefGoogle Scholar
  54. 54.
    Shen J, Chen Z, lin S, et al. Single parabolic band behavior of thermoelectric p-type CuGaTe2. J Mater Chem C, 2016, 4: 209–214CrossRefGoogle Scholar
  55. 55.
    Li W, Lin S, Zhang X, et al. Thermoelectric properties of Cu2SnSe4 with intrinsic vacancy. Chem Mater, 2016, 28: 6227–6232CrossRefGoogle Scholar
  56. 56.
    Pei Y, LaLonde AD, Heinz NA, et al. Stabilizing the optimal carrier concentration for high thermoelectric efficiency. Adv Mater, 2011, 23: 5674–5678CrossRefGoogle Scholar
  57. 57.
    Sanditov DS, Belomestnykh VN. Relation between the parameters of the elasticity theory and averaged bulk modulus of solids. Tech Phys, 2011, 56: 1619–1623CrossRefGoogle Scholar
  58. 58.
    Lin S, Li W, Zhang X, et al. Sb induces both doping and precipitation for improving the thermoelectric performance of elemental Te. Inorg Chem Front, 2017, 4: 1066–1072CrossRefGoogle Scholar
  59. 59.
    Cahill DG, Watson SK, Pohl RO. Lower limit to the thermal conductivity of disordered crystals. Phys Rev B, 1992, 46: 6131–6140CrossRefGoogle Scholar
  60. 60.
    Zhao LD, Zhang BP, Li JF, et al. Thermoelectric and mechanical properties of nano-SiC-dispersed Bi2Te3 fabricated by mechanical alloying and spark plasma sintering. J Alloys Compd, 2008, 455: 259–264CrossRefGoogle Scholar
  61. 61.
    Cui JL, Qian X, Zhao XB. Mechanical and transport properties of pseudo-binary alloys (PbTe)1−x–(SnTe)x by pressureless sintering. J Alloys Compd, 2003, 358: 228–234CrossRefGoogle Scholar
  62. 62.
    MS DARROW WBW, R ROY. Micro-indentation hardness variation as a function of composition for polycrystalline solutions in the systems PbS/PbTe, PbSe/PbTe, and PbS/PbSe. J Mater Sci Technol, 1969, 313–319Google Scholar
  63. 63.
    Zhao L, Wang X, Fei FY, et al. High thermoelectric and mechanical performance in highly dense Cu2−xS bulks prepared by a meltsolidification technique. J Mater Chem A, 2015, 3: 9432–9437CrossRefGoogle Scholar
  64. 64.
    Perumal S, Roychowdhury S, Negi DS, et al. High thermoelectric performance and enhanced mechanical stability of p-type Ge1–xSbxTe. Chem Mater, 2015, 27: 7171–7178CrossRefGoogle Scholar
  65. 65.
    Banik A, Vishal B, Perumal S, et al. The origin of low thermal conductivity in Sn1−xSbxTe: phonon scattering via layered intergrowth nanostructures. Energy Environ Sci, 2016, 9: 2011–2019CrossRefGoogle Scholar
  66. 66.
    Davidow J, Gelbstein Y. A comparison between the mechanical and thermoelectric properties of three highly efficient p-type GeTe-rich compositions: TAGS-80, TAGS-85, and 3% Bi2Te3-doped Ge0.87Pb0.13Te. J Elec Materi, 2012, 42: 1542–1549CrossRefGoogle Scholar
  67. 67.
    Perumal S, Roychowdhury S, Biswas K. Reduction of thermal conductivity through nanostructuring enhances the thermoelectric figure of merit in Ge1−xBixTe. Inorg Chem Front, 2016, 3: 125–132CrossRefGoogle Scholar
  68. 68.
    Rogl G, Grytsiv A, Gürth M, et al. Mechanical properties of half-Heusler alloys. Acta Mater, 2016, 107: 178–195CrossRefGoogle Scholar
  69. 69.
    Zhang L, Rogl G, Grytsiv A, et al. Mechanical properties of filled antimonide skutterudites. Mater Sci Eng-B, 2010, 170: 26–31CrossRefGoogle Scholar
  70. 70.
    Perumal S, Roychowdhury S, Biswas K. High performance thermoelectric materials and devices based on GeTe. J Mater Chem C, 2016, 4: 7520–7536CrossRefGoogle Scholar

Copyright information

© Science China Press and Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  • Binqiang Zhou (周斌强)
    • 1
  • Wen Li (李文)
    • 1
    Email author
  • Xiao Wang (王晓)
    • 1
  • Juan Li (李娟)
    • 1
  • Liangtao Zheng (郑良涛)
    • 1
  • Bo Gao (高博)
    • 1
  • Xinyue Zhang (张馨月)
    • 1
  • Yanzhong Pei (裴艳中)
    • 1
    Email author
  1. 1.Interdisciplinary Materials Research Center, School of Materials Science and EngineeringTongji UniversityShanghaiChina

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