Effects of pressure and strain on spin polarization of IrMnSb
half metals, Heusler materials, spintronics
Journal of Physics Condensed Matter
A high degree of spin polarization in electron transport is one of the most sought-after properties of a material which can be used in spintronics - an emerging technology utilizing a spin degree of freedom in electronic devices. An ideal candidate to exhibit highly spin-polarized current would be a room temperature half-metal, a material which behaves as an insulator for one spin channel and as a conductor for the other spin channel. In this paper, we explore a semi-Heusler compound, IrMnSb, which has been reported to exhibit pressure induced half-metallic transition. We confirm that the bulk IrMnSb is a spin-polarized metal, with dominant contribution to electronic states at the Fermi energy from majority-spin electrons. Application of a uniform pressure shifts the Fermi level into the minority-spin energy gap, thus demonstrating pressure induced half-metallic transition. This behavior is explained by the reduction of the exchange splitting of the spin bands consistent with the Stoner model for itinerant magnetism. We find that the half-metallic transition is suppressed when instead of uniform pressure the bulk IrMnSb is exposed to biaxial strain. This suppression of half-metallicity is driven by the epitaxial strain induced tetragonal distortion, which lifts the degeneracy of the Mn 3d t 2g and e g orbitals and reduces the minority-spin band gap under compressive strain, thus preventing half-metallic transition. Our calculations also indicate that in thin film geometry, surface states emerge in the minority-spin band gap, which has detrimental for practical applications impact on the spin polarization of IrMnSb.
Department of Physics
Original Publication Date
DOI of published version
UNI ScholarWorks, Rod Library, University of Northern Iowa
Tutic, Ibrica; Herran, Juliana; Staten, Bradley; Gray, Paul; Paudel, Tula R.; Sokolov, Andrei; Tsymbal, Evgeny Y.; and Lukashev, Pavel V., "Effects of pressure and strain on spin polarization of IrMnSb" (2017). Faculty Publications. 919.