Half-Metallic Digital Ferromagnetic Heterostructure Composed of aδ-Doped Layer of Mn in Si

Abstract

We propose and investigate the properties of a digital ferromagnetic heterostructure consisting of a delta-doped layer of Mn in Si, using ab initio electronic-structure methods. We find that (i) ferromagnetic order of the Mn layer is energetically favorable relative to antiferromagnetic, and (ii) the heterostructure is a two-dimensional half-metallic system. The metallic behavior is contributed by three majority-spin bands originating from hybridized Mn-d and nearest-neighbor Si-p states, and the corresponding carriers are responsible for the ferromagnetic order in the Mn layer. The minority-spin channel has a calculated semiconducting gap of 0.25 eV. The band lineup is found to be favorable for retaining the half-metal character to near the Curie temperature. This kind of heterostructure may be of special interest for integration into mature Si technologies for spintronic applications.

Fluorination induced half metallicity in two-dimensional few zinc oxide layers

“…As the half-metallic materials are semiconducting in one spin channel while metallic in the opposite spin channel, 100% spin-polarized current flow can be generated. [13][14][15][16][17] This may open new application of 2D ZnO nanomaterials in spintronics.…”

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

“…27,28 The most realistic estimates, based on the disordered local moment (DLM) picture, 30,31 yielded temperature values well below room temperature (≈200 K) for FM DAs, contrary to expectations. 23 Nevertheless, the results are encouraging, since some ferrimagnetic alloys were predicted to be ordered up to room temperature, 27 revealing the potential of the digital doping for fabrication of magnetic semiconductors with high enough transition temperatures.…”

“…According to our calculations, the Ge/Fe I DA is metallic, which is typical for the A IV /TM DAs. 21,[23][24][25]59,60 In the majority spin channel the Fe I d states are almost fully occupied, and in the vicinity of the valence-band maximum their contribution is insignificant, while in the minority spin channel the Fermi level cuts a narrow d states peak leading to the high spin polarization P (E F ) = 82%. The exchange splitting of Fe I d states is around 2 eV.…”

“…[17][18][19][20] For instance, ab initio calculations predict A IV /Mn DAs (A IV = Si,Ge), in which Mn MLs formed substitutionally, to be half metallic ferromagnets. [21][22][23][24][25][26][27][28][29] Recently, the critical temperatures of the intralayer magnetic ordering in A IV /Mn DAs were estimated for the case of easy-axis anisotropy by means of Monte Carlo (MC) simulations. 27,28 The most realistic estimates, based on the disordered local moment (DLM) picture, 30,31 yielded temperature values well below room temperature (≈200 K) for FM DAs, contrary to expectations.…”

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

“…Of course, our model misses some aspects of the numerical calculations, [8][9][10][11][12] such as the orbital degeneracy, the crystalfield splitting, and details of the lattice band structure beyond the effective mass approximation. These aspects can be accounted for in a straightforward way, by proper generalizations of the starting model, equipping the various lattice bands with orbital labels and considering the various hybridizations of (s,p) and d bands allowed by symmetry.…”