The impact of manganese substitution on the structure and properties of tetrahedrite

G.P.L. Guélou (1, 2) , A.V. Powell (1) , R.I. Smith (3, 4) , P. Vaqueiro (1)

1 UOR - University of Reading
2 CRISMAT - Laboratoire de cristallographie et sciences des matériaux
3 RAL - STFC Rutherford Appleton Laboratory
4 ISIS Facility

The crystal structure of the tetrahedrites Cu12 - xMnxSb4S13 (x = 0, 1) has been studied by powder neutron diffraction between room temperature and 773 K. At all temperatures investigated, manganese exclusively occupies tetrahedral sites, while the trigonal-planar sites contain only copper. In situ diffraction data confirm the stability of the tetrahedrite phase up to 773 K, with no evidence of copper mobility at elevated temperatures. Analysis of atomic displacement parameters indicates that there are low-energy vibrations associated with the trigonal-planar and the tetrahedral copper cations. The Einstein temperatures for the copper cations range between 79 and 91 K. Manganese substitution increases the electrical resistivity and the Seebeck coefficient, while the thermal conductivity is reduced. This results in a modest improvement in the thermoelectric figure of merit for Cu12MnSb4S13, which reaches ZT = 0.56 at 573 K. © 2019 Author(s).

Mots clés: Copper; Diffractometers; Manganese; Positive ions; Thermal conductivity; Vibration analysis; Atomic displacement parameters; Einstein temperature; Elevated temperature; In-situ diffraction; Low-energy vibrations; Powder neutron diffraction; Structure and properties; Thermoelectric figure of merit; Crystal structure

Domaines: Chimie; Matériaux; Chimie théorique et/ou physique; Cristallographie

G.P.L. Guélou, A.V. Powell, R.I. Smith, P. Vaqueiro. The impact of manganese substitution on the structure and properties of tetrahedrite. Journal of Applied Physics, 2019, 126 (4), pp.045107. ⟨10.1063/1.5110696⟩. ⟨hal-02278533⟩