Covalent bonding and the nature of band gaps in some half-Heusler compounds
| dc.creator | Kandpal, Hem Chandra | |
| dc.creator | Felser, Claudia | |
| dc.creator | Seshadri, Ram | |
| dc.date | 2005-09-18 | |
| dc.date.accessioned | 2026-07-07T06:26:08Z | |
| dc.date.available | 2026-07-07T06:26:08Z | |
| dc.description | Half-Heusler compounds \textit{XYZ}, also called semi-Heusler compounds, crystallize in the MgAgAs structure, in the space group $F\bar43m$. We report a systematic examination of band gaps and the nature (covalent or ionic) of bonding in semiconducting 8- and 18- electron half-Heusler compounds through first-principles density functional calculations. We find the most appropriate description of these compounds from the viewpoint of electronic structures is one of a \textit{YZ} zinc blende lattice stuffed by the \textit{X} ion. Simple valence rules are obeyed for bonding in the 8-electron compound. For example, LiMgN can be written Li$^+$ + (MgN)$^-$, and (MgN)$^-$, which is isoelectronic with (SiSi), forms a zinc blende lattice. The 18-electron compounds can similarly be considered as obeying valence rules. A semiconductor such as TiCoSb can be written Ti$^{4+}$ + (CoSb)$^{4-}$; the latter unit is isoelectronic and isostructural with zinc-blende GaSb. For both the 8- and 18-electron compounds, when \textit{X} is fixed as some electropositive cation, the computed band gap varies approximately as the difference in Pauling electronegativities of \textit{Y} and \textit{Z}. What is particularly exciting is that this simple idea of a covalently bonded \textit{YZ} lattice can also be extended to the very important \textit{magnetic} half-Heusler phases; we describe these as valence compounds \textit{ie.} possessing a band gap at the Fermi energy albeit only in one spin direction. The \textit{local} moment in these magnetic compounds resides on the \textit{X} site. | |
| dc.description | 18 pages and 14 figures (many in color) | |
| dc.identifier | https://arxiv.org/abs/cond-mat/0509472 | |
| dc.identifier | http://arxiv.org/abs/cond-mat/0509472 | |
| dc.identifier | J. Phys. D. 39 (2006) 776-785 | |
| dc.identifier | doi:10.1088/0022-3727/39/5/S02 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/97022 | |
| dc.subject | Materials Science | |
| dc.subject | Strongly Correlated Electrons | |
| dc.title | Covalent bonding and the nature of band gaps in some half-Heusler compounds | |
| dc.type | text |