Atomic-Scale Engineering of Abrupt Interface for Direct Spin Contact of Ferromagnetic Semiconductor with Silicon

Abstract

Control and manipulation of the spin of conduction electrons in industrial semiconductors such as silicon are suggested as an operating principle for a new generation of spintronic devices. Coherent injection of spin-polarized carriers into Si is a key to this novel technology. It is contingent on our ability to engineer flawless interfaces of Si with a spin injector to prevent spin-flip scattering. The unique properties of the ferromagnetic semiconductor EuO make it a prospective spin injector into silicon. Recent advances in the epitaxial integration of EuO with Si bring the manufacturing of a direct spin contact within reach. Here we employ transmission electron microscopy to study the interface EuO/Si with atomic-scale resolution. We report techniques for interface control on a submonolayer scale through surface reconstruction. Thus we prevent formation of alien phases and imperfections detrimental to spin injection. This development opens a new avenue for semiconductor spintronics.

Engineering of Magnetically Intercalated Silicene Compound: An Overlooked Polymorph of EuSi2

“…It is long known that the first guideline for prediction of new oxide phases containing Eu 2+ is that the proposed phase should have a Sr 2+ analogue . Second, our own experience indicates the equivalence of Eu‐Si and Sr‐Si phase diagrams in the case of surface silicides . It is noteworthy that standard reduction potentials reveal that Eu is by far the most active among magnetic metals, which is important for suppression of hybridization between the intercalated metal and silicene .…”

Making EuO multiferroic by epitaxial strain engineering

“…1-4). Although epitaxial EuO films have been imaged by transmission electron microscopy (TEM) [53][54][55][56][57] , attempts to image these highly strained (EuO) x /(BaO) y superlattices by TEM were unsuccessful.…”

Europium Silicide – a Prospective Material for Contacts with Silicon

“…EuSi 2 crystallizes in the tetragonal α-ThSi 2 structure type ( I41/amd space group) with lattice constants 4.304, 4.304 and 13.65 Å 39 . Europium is highly reactive and its reaction with Si does not require high temperature: EuSi 2 appears as a common side product of EuO growth on Si surfaces 40 41 . At the same time attempts to grow epitaxial films of EuSi 2 have been unsuccessful: resulting in nanoislands and/or polycrystalline films 42 .…”