In:
Journal of Applied Physics, AIP Publishing, Vol. 128, No. 5 ( 2020-08-07)
Abstract:
We report 59Co, 93Nb, and 121Sb nuclear magnetic resonance measurements combined with density functional theory (DFT) calculations on a series of half-Heusler semiconductors, including NbCoSn, ZrCoSb, TaFeSb, and NbFeSb, to better understand their electronic properties and general composition-dependent trends. These materials are of interest as potentially high efficiency thermoelectric materials. Compared to the other materials, we find that ZrCoSb tends to have a relatively large amount of local disorder, apparently antisite defects. This contributes to a small excitation gap corresponding to an impurity band near the band edge. In NbCoSn and TaFeSb, Curie–Weiss-type behavior is revealed, which indicates a small density of interacting paramagnetic defects. Very large paramagnetic chemical shifts are observed associated with a Van Vleck mechanism due to closely spaced d bands splitting between the conduction and valence bands. Meanwhile, DFT methods were generally successful in reproducing the chemical shift trend for these half-Heusler materials, and we identify enhancement of the larger-magnitude shifts, which we connect to electron interaction effects. The general trend is connected to changes in d-electron hybridization across the series.
Type of Medium:
Online Resource
ISSN:
0021-8979
,
1089-7550
Language:
English
Publisher:
AIP Publishing
Publication Date:
2020
detail.hit.zdb_id:
220641-9
detail.hit.zdb_id:
3112-4
detail.hit.zdb_id:
1476463-5
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