Impact of Fe/NaCl (001) interface structure on electronic, magnetic and spin-polarized transport properties of Fe/NaCl/Fe (001) heterojunctions: An ab initio study

Oscillatory exchange coupling and strong direct tunnelling with AgCl based heterojunctions

“…Therefore IC 2 interfacial geometry appears to be favoured. This result is in contrast with the behaviour observed for either Fe/ NaCl (0 0 1) [16] or Fe/CaS (0 0 1) [17] heterointerfaces but agree with the interfacial geometry predicted for Cu/LiCl (0 0 1) heterointerfaces [55]. Additionally, the energy differences between Fe/ AgCl/Fe (0 0 1) heterostructures with IC 1 and IC 2 interfacial geometries are greater than those determined for Fe/NaCl/Fe (0 0 1) and Fe/CaS/Fe (0 0 1) systems.…”

“…Their contributions to the majority-spin conductance depend on the interfacial structure, D 1 states being rather decoupled for the interfacial configuration with Fe atoms located above the hollow sites between Ca and S atoms. IRSs were found to play a major role on the spin-polarized transport for both NaCl and CaS based tunnel junctions and depending on Fe/NaCl(CaS) (0 0 1) interfacial geometry, extremely large TMR values have been predicted [16,17]. D 1 band symmetry selection of NaCl barrier and the possibility to obtain large TMR values by combining the direct and resonant tunnelling have been confirmed by the recent study of FePt/NaCl/FePt tunnel junctions [36].…”

“…[16]. The bcc-type structure is considered for Fe electrodes and B1-type structure for AgCl spacers.…”

“…First-principles studies performed for Fe/ZnSe/Fe heterostructures have shown that the exchange coupling between Fe electrodes across ZnSe barriers is interface termination sensitive and oscillate between FM and AFM states when increasing the barrier thickness [14]. Recent first-principles investigations of Fe/NaCl/Fe (0 0 1) [15,16] and Fe/ CaS/Fe (0 0 1) [17] heterostructures have revealed the presence of small exchange couplings with exponential decays as function of the barriers thickness, in qualitative agreement with the spin-current model of Slonczewski [18] and quantum-interference model of Bruno [19]. Although the strength and the sign of the couplings relate rather with the properties of the electrode/barrier electronic http://dx.doi.org/10.1016/j.jallcom.2015.01.023 0925-8388/Ó 2015 Elsevier B.V. All rights reserved.…”

“…Thus the interface resonant states (IRSs) at interfaces have been proven to have a large impact on the spin polarized transport properties and TMR magnitudes [20,21,23,[30][31][32][33][34][35]. Ab initio studies of Fe/NaCl/Fe (0 0 1) tunnel junctions have shown mostly D 1 band symmetry selection for the majority-spin FM conductances that present a pronounced peak around C point [16]. In addition, the majority-spin FM conductance is sensitive to the interfacial geometry.…”