Phys.org November 6, 2022
An international team of researchers (France, Japan, Germany) 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, they showed that the materials were 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, they discussed the structure–thermoelectric properties relationships and clarified the interesting crystal chemistry in this system. They demonstrated that excess Cu+ substituted for Mn2+ dopes holes into the top of the valence band, leading to a remarkable enhancement of the power factor and figure of merit ZT…read more. Open Access TECHNICAL ARTICLEÂ
Crystal structure representation of Cu2MGeS4 phases with a) a tetragonal stannite-type structure (M=Fe, Co, Hg)… Credit: Angewandte Chemie International Edition, 13 September 2022.Â