Influence of interface structure on electronic properties and Schottky barriers inFe∕GaAsmagnetic junctions

Abstract

The electronic and magnetic properties of Fe/GaAs(001) magnetic junctions are investigated using first-principles density-functional calculations. Abrupt and intermixed interfaces are considered, and the dependence of charge transfer, magnetization profiles, Schottky barrier heights, and spin polarization of densities of states on interface structure is studied. With As-termination, an abrupt interface with Fe is favored, while Ga-terminated GaAs favors the formation of an intermixed layer with Fe. The Schottky barrier heights are particularly sensitive to the abruptness of the interface. A significant density of states in the semiconducting gap arises from metal interface states. These spin-dependent interface states lead to a significant minority spin polarization of the density of states at the Fermi level that persists well into the semiconductor, providing a channel for the tunneling of minority spins through the Schottky barrier. These interface-induced gap states and their dependence on atomic structure at the interface are discussed in connection with potential spin-injection applications.

Interface Magnetism in Ferromagnetic Metal–compound Semiconductor Hybrid Structures

“…Utilizing the element specificity of XMCD, the orbital-and spin-components of the Fe magnetic moments were extracted, demonstrating a bulk-like value for the Fe spin magnetic moment and a large enhancement in the orbital magnetic moment due to the reduced symmetry at the interface. (Bulk-like Fe magnetic moments at the Fe/GaAs(001) interface were later theoretically predicted by calculations of Demchenko and Liu 91 , and Tobin et al have used spin-resolved photoelectron spectroscopy to also reveal bulk-like magnetism at the Fe/GaAs(001) interface, despite significant intermixing 74 . )…”

“…From a theoretical point of view, Erwin et al suggested that Fe adsorption causes the characteristic As-dimers of the reconstructed GaAs(001) surface to become unstable 90 . With this in mind, density functional theory calculations, carried out by Demchenko and Liu, assuming an interface structure based on the GaAs(001)-(1 × 1) reconstruction, suggest that, due to the preference for FeAs over Fe-Ga interfacial bonding, As-terminated Fe/GaAs(001) favours an atomically abrupt interface whilst the Ga-terminated structure favours an intermixed interface region over several atomic planes 91 . Driven by these theoretical predictions, efforts to unambiguously determine the detailed atomic structure of the buried Fe/GaAs(001) interface experimentally have begun.…”

Thermal electric effects in Fe|GaAs|Fe tunnel junctions

“…44 First principle studies show favorable abrupt interface for the As-terminated interface while rough interface for Ga-terminated interface. 46 In this papere, we focus on the As-terminated MTJ. And assume a small concentration of interstitial Fe impurity is possible in the experiment, with the interfacial Fe is placed at the planer center of the interfacial As atoms.…”

The evolution of Ga and As core levels in the formation of Fe∕GaAs (001): A high resolution soft x-ray photoelectron spectroscopic study

“…These experimental data on the early stages of Fe/GaAs interface development are in good general agreement with the associated theoretical models. [14][15][16] In a bid to counter substrate disruption, several preventative strategies have been invoked, including the use of buffer layers 13,17,18 and passivation 19,20 of the substrate surface.…”