Emission properties of InGaAs/GaAs heterostructures with δ⟨Mn⟩-doped barrier

Abstract

Light-emitting device heterostructures with a δ⟨Mn⟩-doped layer inserted between the Schottky contact and near-surface InGaAs/GaAs quantum well (QW) have been fabricated. The δ⟨Mn⟩-doped layer facilitates hole tunnelling from the Schottky contact to the QW and impedes that of QW electrons in the opposite direction. It leads to a highly enhanced electroluminescence signal from the InGaAs QW. An effective p–d exchange interaction of holes with magnetic moments of Mn ions is found to strongly enhance the effective hole g-factor and the circular polarization of the low (∼2 K) temperature emission up to 20% in magnetic fields of 1–2 T.

Spin-polarized half-metallic state of a ferromagneticδlayer in a semiconductor host

“…As far as the physics of systems with a channel is concerned, [4][5][6] in the absence of clear experimental indications, we can provide some indicative predictions about the behavior of the FM critical temperature T c with varying distance d between the channel and the δ layer. In Sec.…”

“…For example, III-V DMHs of this type have been grown and studied, in which a δ layer of Mn was deposited close to a quantum well (also called channel) at some distance (called spacer) d from it. [4][5][6] The effect of the channel on magnetism in such multicomponent systems is threefold. First, the quantum magnetic proximity effect (interpenetration of the wave function tails both into the channel and into the δ layer) modifies the effective exchange integral between the local spins of magnetic ions in the δ layer and polarizes the free carrier spins in the channel.…”

“…Further lines of investigation include the mechanism of exchange coupling among different δ layers when they are organized into a periodic structure, 2,3 and the feedback of the channel on the magnetic properties of the δ layer. [4][5][6][7] As far as the first aspect is concerned, to evaluate the exchange interaction between two magnetic δ layers, in Ref. 18 we introduced a phenomenological model which assumed FM order within each δ layer as the starting point, and showed that there are two main mechanisms, which lead to the competition of FM and AFM coupling between two neighboring δ layers.…”

“…2,3 Little attention has been devoted, so far, to DMHs in which 3d-magnetic metal δ layers are inserted into a IV-group semiconductor (Si or Ge) host, although these systems are the more natural candidates to realize full integration of spintronics with standard Si-based electronics. While initially the magnetic properties of DMHs were attributed to the interplay of the different δ layers, or to the presence of free carriers in systems with a quantum-well carrier channel parallel to the δ layer, [4][5][6] increasing experimental evidence indicates that magnetism can be ascribed even to an individual δ layer, 2,7 while the channel or the periodic arrangement of δ layers may introduce some interesting modifications.…”

Search for stable ferromagnets amongAIV/Fe digital alloys (AIV=Si, Ge) using first-principles calculations

“…Such a way of preparation allows tailoring the magnetic properties of the samples freely by changing the TM atoms' concentration or semiconductor spacer thickness and can yield to high Curie temperature. 8,9 In combination with high-mobility modulation-doped heterostructures [10][11][12][13] ferromagnetic (FM) DAs would become attractive for spin-transport applications, 14 provided that they remain magnetically ordered above room temperature.…”