Influence of p- and n-type doping on the transport properties of the Nowotny chimney-ladder compounds RuAl 2 and RuGa 2

Nowotny chimney-ladder compounds RuAl 2 and RuGa 2 have been substituted with p- and n-type dopants to study the resistivity, Seebeck and Hall coefficients, and thermal conductivity of resulting compounds in the temperature range of 80–300 K. The resistivity and Seebeck coefficient suggest that thes...

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Bibliographic Details
Published in:Journal of materials research 2011-08, Vol.26 (15), p.1907-1912
Main Authors: Ponnambalam, V., Lehr, Gloria, Morelli, Donald T.
Format: Article
Language:English
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Summary:Nowotny chimney-ladder compounds RuAl 2 and RuGa 2 have been substituted with p- and n-type dopants to study the resistivity, Seebeck and Hall coefficients, and thermal conductivity of resulting compounds in the temperature range of 80–300 K. The resistivity and Seebeck coefficient suggest that these compounds are degenerate semiconductors. Hall measurements reveal that the carrier concentration has indeed been changed by an order of magnitude, particularly in p-type RuGa 2 by substituting Cr and Mn. Compared to p-type samples, the resistivity is an order of magnitude larger for n-type samples, for a similar level of carrier concentration. Interestingly, the hole mobility is two to three orders of magnitude larger, reaching the highest value of ∼750 cm 2 /V·s. The electron mobility is temperature independent and is typically in the range of ∼1–4 cm 2 /V·s. Thermal conductivity shows characteristics of mixed scattering with impurity scattering contributing appreciably in heavily substituted compositions.
ISSN:0884-2914
2044-5326
DOI:10.1557/jmr.2011.126