Direct observation of the electronic structure in thermoelectric half-Heusler alloys Zr{sub 1−x}M{sub x}NiSn (M = Y and Nb)
- Department of Frontier Materials, Nagoya Institute of Technology, Nagoya 466-8555 (Japan)
This study investigates the electronic and local crystal structures of the hole-doped Zr{sub 1−x}Y{sub x}NiSn and electron-doped Zr{sub 1−x}Nb{sub x}NiSn alloys using synchrotron radiation photoemission spectroscopy (SR-PES) and synchrotron radiation X-ray powder diffraction (SR-XRD) measurements, thereby clarifying the mechanisms underlying the thermoelectric performance of the p- and n-type alloys. SR-XRD analysis reveals an interstitial Ni disorder in the half-Heusler structure and the substitution of the dopant Y and Nb atoms at the Zr site. SR-PES result shows that the variation in the electronic structure of the alloys due to doping can be explained on the basis of the rigid band model. The asymmetric pseudo-gap near the Fermi level, which is rather unexpected from the band structure calculation because of the presence of the interstitial Ni disorder, could possibly be the reason underlying poor thermoelectric performance of p-type half-Heusler ZrNiSn alloys when compared with the n-type counterparts.
- OSTI ID:
- 22410256
- Journal Information:
- Journal of Applied Physics, Vol. 117, Issue 20; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COMPARATIVE EVALUATIONS
CRYSTAL STRUCTURE
DOPED MATERIALS
ELECTRONIC STRUCTURE
FERMI LEVEL
HEUSLER ALLOYS
HOLES
NICKEL ALLOYS
NIOBIUM ALLOYS
PHOTOELECTRON SPECTROSCOPY
SYNCHROTRON RADIATION
TIN ALLOYS
VARIATIONS
X-RAY DIFFRACTION
YTTRIUM ALLOYS
ZIRCONIUM BASE ALLOYS