A detailed look beneath the surface: Evidence of a surface reconstruction beneath a capping layer

Krull, Dominique; Tesch, Marc F.; Schönbohm, Frank; Lühr, Tobias; Keutner, Christoph; Berges, U.; Mertins, H.-Ch.; Westphal, C.

doi:10.1016/j.apsusc.2016.01.162

Cited by 1 publication

(3 citation statements)

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“…Since the c(8 × 2) surface component at 215.1 eV vanishes, a lift of the Ga-rich surface reconstruction is suggested, again. This is different from the results obtained for the Fe/GaAs(0 0 1) layer system, where Fe preserves the GaAs(0 0 1) surface reconstruction [51]. In the case of Co deposition on GaAs, the surface reconstruction is lifted due to a strong interaction between Co and Ga.…”

Section: Co(bcc)/gaas(0 0 1) Interfacecontrasting

confidence: 78%

“…Compared to the pure Ga 3d signal (blue line), both new components are shifted to higher kinetic energies by roughly 0.8 eV. According to literature, the pure Ga 3d signal contains three components, referring to two surface states and one bulk state since GaAs c(8 × 2) is a Ga-rich surface reconstruction [45][46][47][48][49][50][51]. The bulk state at 236.5 eV is no longer detectable, since it is buried beneath the Co layer.…”

Section: Co(bcc)/gaas(0 0 1) Interfacementioning

confidence: 92%

“…Additionally, the strong GaAs(0 0 1) c(8 × 2) surface reconstruction component displayed in the clean As 3d spectrum in figure 8 (bottom) has vanished. According to literature, the pure As 3d signal contains two components referring to one surface state and one bulk state [45][46][47][48][49][50][51]. The bulk state at 214.6 eV is no longer detectable like the Ga 3d bulk state.…”

Section: Co(bcc)/gaas(0 0 1) Interfacementioning

confidence: 99%

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Revealing the interfaces of the hybrid system MgO/Co/GaAs(0 0 1): a structural and chemical investigation with XPS and XPD

Shamout¹,

Espeter²,

Roese³

et al. 2018

J. Phys.: Condens. Matter

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Bcc metals and MgO are used in technological research for building magnetic tunnel junctions (MTJs), because they yield a high tunnel magnetoresistance. Thin insulating barriers are of great importance in realizing MTJs. Combined with electrons spin-injected into GaAs, tunneled electrons can be detected and manipulated. We report on a synchrotron radiation based x-ray photoelectron spectroscopy and x-ray photoelectron diffraction study on the system MgO/Co(bcc)/GaAs(0 0 1) for ultra-low Co and MgO coverages ([Formula: see text], [Formula: see text]). As a result, we obtain a CoGa alloy at the Co/GaAs interface in the rare D0 structure. This structure is only 6.07 Å thick, and serves as a template for the metastable Co(bcc) structure. Co(bcc) itself grows heavily distorted in the (0 0 1) direction for the first two unit cells, due to the D0 template. The MgO/Co interface reveals a weak bonding between MgO and Co(bcc) without Co oxidation, since no compound formation was observed. Additionally, MgO grows in an amorphous phase for a thickness of [Formula: see text]. At [Formula: see text], it crystallizes in a compressed unit cell where every second layer is shifted toward the (0 0 1) direction compared to the bulk halite structure.

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Section: Co(bcc)/gaas(0 0 1) Interfacecontrasting

confidence: 78%