skip to main content

Title: Direct observation of the electronic structure in thermoelectric half-Heusler alloys Zr{sub 1−x}M{sub x}NiSn (M = Y and Nb)

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.
Authors:
; ; ; ;  [1]
  1. Department of Frontier Materials, Nagoya Institute of Technology, Nagoya 466-8555 (Japan)
Publication Date:
OSTI Identifier:
22410256
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 20; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, 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