Interplay of growth mode and thermally induced spin accumulation in epitaxial Al/Co${}_2$TiSi/Al and Al/Co${}_2$TiGe/Al contacts

Abstract

The feasibility of thermally driven spin injectors built from half-metallic Heusler alloys inserted between aluminum leads was investigated by means of {\em ab initio} calculations of the thermodynamic equilibrium and electronic transport. We have focused on two main issues and found that: (i) the interface between Al and the closely lattice-matched Heusler alloys of type Co${}_2$Ti$Z$ ($Z=$ Si or Ge) is stable under various growth conditions; and (ii) the conventional and spin-dependent Seebeck coefficients in such heterojunctions exhibit a strong dependence on both the spacer and the atomic composition of the Al/Heusler interface. The latter quantity gives a measure of the spin accumulation and varies between $+8$~$\mu$V/K and $-3$~$\mu$V/K near $300$~K, depending on whether a Ti-Ge or a Co-Co plane makes the contact between Al and Co${}_2$TiGe in the trilayer. Our results show that it is in principle possible to tailor the spin-caloric effects by a targeted growth control of the samples.

16 pages, 13 figures

References in corpus (10)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Calculated electronic and magnetic properties of the half-metallic, transition metal based Heusler compounds
• Non-quasiparticle states in Co${}_2$MnSi evidenced through magnetic tunnel junction spectroscopy measurements
• Spin caloritronics in magnetic tunnel junctions: Ab initio studies
• First-principles study of thin magnetic transition-metal silicide films on Si(001)
• Structural stability, magnetic and electronic properties of Co2MnSi(001)/MgO heterostructures: A density functional theory study
• Spin injection from Fe into Si(001): ab initio calculations and role of the Si complex band structure
• Magneto-electric and thermo-magneto-electric effects in ferromagnetic transition-metal alloys from first-principles
• Spin-caloric transport properties of cobalt nanostructures: spin disorder effects from first principles
• Influence of tetragonal distortion on the magnetic and electronic properties of the Heusler compound Co2TiSn from first principles

Cited by in corpus (10)

• Fundamental difference in the electronic reconstruction of infinite-layer vs. perovskite neodymium nickelate films on SrTiO${}_3$(001)
• Design of $n$- and $p$-type oxide thermoelectrics in LaNiO${}_3$/SrTiO${}_3(001)$ superlattices exploiting interface polarity
• Confinement- and strain-induced enhancement of thermoelectric properties in LaNiO${}_3$/LaAlO${}_3(001)$ superlattices
• Spincaloric properties of epitaxial Co${}_2$MnSi/MgO/Co${}_2$MnSi magnetic tunnel junctions
• Correlated interface electron gas in infinite-layer nickelate versus cuprate films on SrTiO${}_3$(001)
• Inducing $n$- and $p$-type thermoelectricity in oxide superlattices by strain tuning of orbital-selective transport resonances
• Native defects in the Co${}_2$Ti$Z$ ($Z=$ Si, Ge, Sn) full Heusler alloys: formation and influence on the thermoelectric properties
• Competition of defect ordering and site disproportionation in strained LaCoO${}_3$ on SrTiO${}_3$(001)
• Nature of the magnetic coupling in infinite-layer nickelates versus cuprates
• Spin transport and spin-caloric effects in (Cr,Zn)Te half-metallic nanostructures: Effect of spin disorder at elevated temperatures from first principles