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Hall‐effect Measurements and Transport Properties of Heterostructures in the Model System NiTe 2 ‐Sn 12 Sb 2 Te 15
Author(s) -
Fraunhofer Christina,
Schwarzmüller Stefan,
Gardiner James L.,
Snyder G. Jeffrey,
Oeckler Oliver
Publication year - 2020
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.202000224
Subject(s) - thermoelectric effect , heterojunction , figure of merit , condensed matter physics , hall effect , doping , charge carrier , seebeck coefficient , materials science , charge (physics) , electrical resistivity and conductivity , reproducibility , composite number , physics , chemistry , thermodynamics , optoelectronics , composite material , quantum mechanics , chromatography
In composite materials of NaCl‐type Sn 12 Sb 2 Te 15 with x equivalents of CdI 2 ‐type NiTe 2 ( x = 0.2; 1; 2), both phases are stable from room temperature up to 500 °C without a significant extent of mutual doping. The thermoelectric properties of this model system, complemented by Hall measurements, show clear trends with increasing x . Both electrical and thermal conductivities increase significantly whilst Seebeck coefficients decrease due to an increase in charge carrier concentrations. The overall Figure of merit zT is slightly impaired upon heterostructuring with NiTe 2 . However, the good reproducibility and cyclability of the measurements renders these composites an intriguing model system to qualitatively examine the applicability of a simple single parabolic band (SPB) model based on Hall‐effect data to rather metallic heterostructures. This model is best applicable to composites with lower fractions of NiTe 2 and gives the direction for tuning the charge carrier concentrations toward the optimum upon heterostructuring. These findings are in accordance with B ‐factor analysis and classical effective medium theory for spheroidal precipitates.