English
 
User Manual Privacy Policy Disclaimer Contact us
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT

Released

Journal Article

Thermoelectric Performance of the Half-Heusler Phases RNiSb (R = Sc, Dy, Er, Tm, Lu): High Mobility Ratio between Majority and Minority Charge Carriers

MPS-Authors
/persons/resource/persons126891

Veremchuk,  I.
Igor Veremchuk, Chemical Metal Science, Max Planck Institute for Chemical Physics of Solids, Max Planck Society;

/persons/resource/persons126626

Grin,  Yu.
Juri Grin, Chemical Metal Science, Max Planck Institute for Chemical Physics of Solids, Max Planck Society;

External Ressource
No external resources are shared
Fulltext (public)
There are no public fulltexts stored in PuRe
Supplementary Material (public)
There is no public supplementary material available
Citation

Ciesielski, K., Synoradzki, K., Veremchuk, I., Skokowski, P., Szymanski, D., Grin, Y., et al. (2020). Thermoelectric Performance of the Half-Heusler Phases RNiSb (R = Sc, Dy, Er, Tm, Lu): High Mobility Ratio between Majority and Minority Charge Carriers. Physical Review Applied, 14(5): 054046, pp. 1-15. doi:10.1103/PhysRevApplied.14.054046.


Cite as: http://hdl.handle.net/21.11116/0000-0007-8D3C-8
Abstract
Deeper understanding of electrical and thermal transport is critical for further development of thermoelectric materials. Here we describe the thermoelectric performance of a group of rare-earth-bearing half-Heusler phases determined in a wide temperature range. Polycrystalline samples of ScNiSb, DyNiSb, ErNiSb, TmNiSb, and LuNiSb are synthesized by arc melting and densified by spark plasma sintering. They are characterized by powder x-ray diffraction and scanning electron microscopy. The physical properties are studied by means of heat-capacity and Hall-effect measurements performed in the temperature range from 2 to 300 K, as well as electrical-resistivity, Seebeck-coefficient, and thermal-conductivity measurements performed in the temperature range from 2 to 950 K. All the materials except TmNiSb are found to be narrow-gap intrinsic p-type semiconductors with rather light charge carriers. In TmNiSb, the presence of heavy holes with large weighted mobility is evidenced by the highest power factor among the series (17 mu W K-2 cm(-1) at 700 K). The experimental electronic relaxation time calculated with the parabolic band formalism is found to range from 0.8 x 10(-14) to 2.8 x 10(-14) s. In all the materials studied, the thermal conductivity is between 3 and 6 W m(-1) K-1 near room temperature (i.e., smaller than in other pristine d-electron half-Heusler phases reported in the literature). The experimental observation of the reduced thermal conductivity appears fully consistent with the estimated low sound velocity as well as strong point-defect scattering revealed by Debye-Callaway modeling. Furthermore, analysis of the bipolar contribution to the measured thermal conductivity yields abnormally large differences between the mobilities of n-type and p-type carriers. The latter feature makes the compounds examined excellent candidates for further optimization of their thermoelectric performance via electron doping.