The influence of d10-d10 interactions in Ag5Te1.8Se0.2Cl and Ag5Te1.6Se0.4Cl on structural and thermoelectric properties

Nadine Eckstein (1) , Jean-Louis Bobet (2) , Bernard Chevalier (2) , Tom Nilges (1)

1 Institut für Anorganische und Analytische Chemie
2 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux

Measurements of the thermopower and of the thermal diffusivity and a detailed analysis of the structural features by temperature-dependent single-crystal structure determinations of silver ionconducting Ag5Te1.8Se0.2Cl and Ag5Te1.6Se0.4Cl were performed to investigate the interaction of silver ions in their disordered state. The substituted phases show an order/disorder phase transition at 273.3(2) and 302.5(2) K, respectively, accompanied by a drop of the thermal diffusivity and a minimum plateau of the thermopower right after the transition. Silver ions are arranged in welldefined strands along the crystallographic c axis characterized by a set of not fully occupied sites. Ag5Te1.6Se0.4Cl shows a negative thermal expansion during temperature rise right after the silver order/disorder phase transition; this is explicable by attractive d10-d10 interactions within the disordered silver substructure. After the minimum values of the thermopower have been reached, these values rise in parallel to the decrease of the d10-d10 interactions. Ag5Te1.6Se0.4Cl shows a very low value of the thermal diffusivity of 0.070 mm2 s−1 at 300.7 K.

Mots clés: Silver; Tellurium; Polytelluride; Thermoelectrics; d10-d10 Interactions

Domaines: Matériaux

Nadine Eckstein, Jean-Louis Bobet, Bernard Chevalier, Tom Nilges. The influence of d10-d10 interactions in Ag5Te1.8Se0.2Cl and Ag5Te1.6Se0.4Cl on structural and thermoelectric properties. Zeitschrift fur Naturforschung B, 2011, 66 (10), pp.1005-1014. ⟨10.5560/ZNB.2011.66b1005⟩. ⟨hal-00643613⟩