Minority-spin band parameters in a NiMnSb thin film determined by spectral conductivity

NiMnSb is expected to be a ferromagnetic half metal, an expectation that is based in part on band structure calculations. Here we report optical conductivity studies of the band structure for a film prepared by pulsed laser deposition onto a Si substrate held at a relatively low temperature as is re...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:Journal of applied physics 2004-12, Vol.96 (11), p.6421-6424
Hauptverfasser: Grigorescu, C. E. A., Trodahl, H. J., Strickland, N. M., Bittar, A., Manea, S. A., Giapintzakis, J., Monnereau, O., Notonier, R., Kennedy, V. J.
Format: Artikel
Sprache:eng
Schlagworte:
Online-Zugang:Volltext
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
Beschreibung
Zusammenfassung:NiMnSb is expected to be a ferromagnetic half metal, an expectation that is based in part on band structure calculations. Here we report optical conductivity studies of the band structure for a film prepared by pulsed laser deposition onto a Si substrate held at a relatively low temperature as is required for some device applications—films which are susceptible to site disorder associated with the vacant site in this half-Heusler compound. We demonstrate that the direct interband transitions are essentially unshifted in comparison with bulk material, though they are somewhat broadened. Below the direct-transition absorption edge we report the presence of indirect spin-reversing transitions between the Fermi energy (Ef) and the extrema of the minority-spin valence and conduction bands, providing a measure of the band edge energies. Both of these edges appear closer to Ef than is seen in well-ordered bulk NiMnSb, with the conduction-band minimum showing weight at only 200cm−1 above Ef, close enough to have substantial occupation at ambient temperature.
ISSN:0021-8979
1089-7550
DOI:10.1063/1.1811779