Surface x-ray diffraction analysis of the MgO/Fe(001) interface: Evidence for an FeO layer

Meyerheim, H. L.; Popescu, Radian; Jedrecy, N.; Vedpathak, M.; Sauvage‐Simkin, M.; Pinchaux, R.; Heinrich, B.; Kirschner, J.

doi:10.1103/physrevb.65.144433

Cited by 106 publications

(67 citation statements)

References 26 publications

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“…The Fe/MgO was modeled by an Fe monolayer on a six-atomic-layer MgO(001) substrate, where Fe atoms locate on top of the O atoms, assuming the in-plane lattice constant matching to the calculated value of bulk MgO while the out-of-plane coordinates of Fe atoms are fully optimized using the atomic-force FLAPW calculations. Note that the structural parameter obtained within LSDA qualitatively agree with those analyzed by surface X-ray diffraction 33 as demonstrated previously.…”

Section: Electronic Band Structuresupporting

confidence: 85%

Dirac fermions in a Fe ultrathin film

Zhang

Nakamura

et al. 2015

Phys. Rev. B

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We show the existence of massive Dirac fermions in electronic band structures of a few Fe atomic layers with perpendicular magnetization. Based on a tight binding model fitted to ab-initio band structure, we observe four distinct massive Dirac fermions near the Fermi level, which result from atomic spin-orbit coupling of Fe and a band inversion between Fe 4s-3d x 2 −y 2 hybrid orbital band and 3dxy orbital band. These lead to a valence band with finite Chern integer (+2) and chiral edge modes near the Fermi level. When the chemical potential is set inside the Dirac gap by carrier doping, the Hall conductivity exhibits a plateau-like structure with quantized value 2(e 2 /h), and orbital magnetization shows a prominent increase, latter of which is mostly due to chiral orbital motion of electrons along the edge modes. We discuss the stability of the Dirac fermions in Fe(001) monolayer on MgO(001) substrate and Fe(001) bilayer case.

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Section: Electronic Band Structuresupporting

confidence: 85%

Dirac fermions in a Fe ultrathin film

Zhang

Nakamura

et al. 2015

Phys. Rev. B

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“…Throughout this work a parameterization following Vosko, Wilk, and Nusair 29 was used. Since structural information of Fe/MgO/Fe MTJs with embedded ultrathin Cr and Co spacers are not reported so far, we resort to a geometry of planar Fe(001)/MgO/Fe(001) junctions which has been determined experimentally by surface x-ray diffraction analyses 30,31 . This structure has been used in previous theoretical studies 16,32 .…”

Section: Theoretical Backgroundmentioning

confidence: 99%

Tailoring tunnel magnetoresistance by ultrathin Cr and Co interlayers: A first-principles investigation of Fe/MgO/Fe junctions

et al. 2010

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We report on systematic ab-initio investigations of Co and Cr interlayers embedded in Fe(001)/MgO/Fe(001) magnetic tunnel junctions, focusing on the changes of the electronic structure and the transport properties with interlayer thickness. The results of spin-dependent ballistic transport calculations reveal options to specifically manipulate the tunnel magnetoresistance ratio. The resistance area products and the tunnel magnetoresistance ratios show a monotonous trend with distinct oscillations as a function of the Cr thickness. These modulations are directly addressed and interpreted by means of magnetic structures in the Cr films and by complex band structure effects. The characteristics for embedded Co interlayers are considerably influenced by interface resonances which are analyzed by the local electronic structure.

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“…The structures, shown in Figure 1, were based on the coordinates given in [8], and include 5 atomic layers of MgO; the lattice constant of the Fe electrodes was held fixed at a = 2.866Å. The properties were calculated at the Fermi energy using 40,401 k-points, equally distributed in the Brillouin zone parallel to the interfaces, and at the k-point (k x , k y ) = (0, 0) using 401 equally spaced energy points.…”

Section: Modelmentioning

confidence: 99%

“…The top-most atomic layer of the Fe substrate, unfortunately, seems to oxidize during MgO growth, and an atomic layer of FeO probably exists at the Fe-MgO interface in such devices [7], [8], although Fe-MgO-Fe can probably be grown without such a layer [9]. These FeO layers have a very significant effect on the electrical properties of the devices [10], and the TMR is predicted to be much smaller for Fe-FeOMgO-Fe devices than for Fe-MgO-Fe devices [10], [11].…”

Section: Introductionmentioning

confidence: 99%