Published September 13, 2022 | Version v1
Journal article Open

Engineering Transport Properties in Interconnected Enargite-Stannite Type Cu2+xMn1−xGeS4 Nanocomposites

  • 1. CRISMAT, CNRS, Normandie Univ, ENSICAEN, UNICAEN, 14000 Caen, France
  • 2. College of Physics and Institute of Advanced Interdisciplinary Studies, Chongqing University, Chongqing 401331, China Analytical and Testing Center of Chongqing University, Chongqing 401331, China
  • 3. Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, Osaka 565-0871, Japan
  • 4. Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187, Dresden, Germany
  • 5. Univ Rennes, CNRS, ISCR – UMR 6226, F-35000 Rennes, France
  • 6. Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka 816-8580, Japan


Understanding the mechanism that connects heat and electron transport with crystal structures and defect chemistry is fundamental to develop materials with thermoelectric properties. In this work, we synthesized a series of self-doped compounds Cu2+xMn1-xGeS4 through Cu for Mn substitution. Using a combination of powder X-ray diffraction, high resolution transmission electron microscopy and precession-assisted electron diffraction tomography, we evidence that the materials are composed of interconnected enargite- and stannite-type structures, via the formation of nanodomains with a high density of coherent interfaces. By combining experiments with ab-initio electron and phonon calculations, we discuss the structure–thermoelectric properties relationships and clarify the interesting crystal chemistry in this system. We demonstrate that excess Cu+ substituted for Mn2+ dope holes into the top of the valence band, leading to a remarkable enhancement of the power factor and figure of merit ZT.


Angew Chem Int Ed - 2022 - Pavan Kumar - Engineering Transport Properties in Interconnected Enargite‐Stannite Type Cu2 xMn1.pdf

Additional details



EMC3 – Energy Materials and Clean Combustion Center ANR-10-LABX-0009
Agence Nationale de la Recherche
NanED – Electron Nanocrystallography 956099
European Commission