Exchange-Mediated Anisotropy of (Ga,Mn)As Valence-Band Probed by Resonant Tunneling Spectroscopy

Elsen, M.; Jaffrès, Henri; Mattana, R.; Tran, Minh-Tien; George, Jean-Marie; Miard, A.; Lemaı̂tre, A.

doi:10.1103/physrevlett.99.127203

Cited by 26 publications

(33 citation statements)

References 17 publications

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“…We used E F and the deformation anisotropic term 79 Q e as fitting parameters, which were determined so that the relationship between the calculated resonant tunneling energy E R (relative to the Fermi level) and measured V R becomes linear, that is, the V R À E R relation is expressed by V R ¼ sE R , where s is a fitting parameter corresponding to the slope of V R À E R . [79][80][81] The color-coded d Fig. 11(b).…”

Section: à3mentioning

confidence: 99%

Recent progress in III-V based ferromagnetic semiconductors: Band structure, Fermi level, and tunneling transport

Tanaka

Ohya

Hai

2014

Applied Physics Reviews

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Spin-based electronics or spintronics is an emerging field, in which we try to utilize spin degrees of freedom as well as charge transport in materials and devices. While metal-based spin-devices, such as magnetic-field sensors and magnetoresistive random access memory using giant magnetoresistance and tunneling magnetoresistance, are already put to practical use, semiconductor-based spintronics has greater potential for expansion because of good compatibility with existing semiconductor technology. Many semiconductor-based spintronics devices with useful functionalities have been proposed and explored so far. To realize those devices and functionalities, we definitely need appropriate materials which have both the properties of semiconductors and ferromagnets. Ferromagnetic semiconductors (FMS), which are alloy semiconductors containing magnetic atoms such as Mn and Fe, are one of the most promising classes of materials for this purpose, and thus have been intensively studied for the past two decades. Here, we review the recent progress in the studies of the most prototypical III-V based FMS, p-type (GaMn)As, and its heterostructures with focus on tunneling transport, Fermi level, and bandstructure. Furthermore, we cover the properties of a new n-type FMS, (InFe)As, which shows electron-induced ferromagnetism. These FMS materials having zinc-blende crystal structure show excellent compatibility with well-developed III-V heterostructures and devices.

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Section: à3mentioning

confidence: 99%

Recent progress in III-V based ferromagnetic semiconductors: Band structure, Fermi level, and tunneling transport

Tanaka

Ohya

Hai

2014

Applied Physics Reviews

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“…While the corresponding parameters for (Ga,Mn)As are not known, the use of GaAs parameters appears reasonable. We note, for example, that GaAs parameters adequately described tunnelling anisotropic magnetoresistance in recent experiments [26]. Finally, we demonstrate that the current-induced effective SO field H so is sufficient to reversibly manipulate the direction of magnetization.…”

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confidence: 83%

Evidence for reversible control of magnetization in a ferromagnetic material by means of spin–orbit magnetic field

et al. 2009

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Conventional computer electronics creates a dichotomy between how information is processed and how it is stored. Silicon chips process information by controlling the flow of charge through a network of logic gates. This information is then stored, most commonly, by encoding it in the orientation of magnetic domains of a computer hard disk. The key obstacle to a more intimate integration of magnetic materials into devices and circuit processing information is a lack of efficient means to control their magnetization. This is usually achieved with an external magnetic field or by the injection of spin-polarized currents [1,2,3]. The latter can be significantly enhanced in materials whose ferromagnetic properties are mediated by charge carriers [4]. Among these materials, conductors lacking spatial inversion symmetry couple charge currents to spin by intrinsic spin-orbit (SO) interactions, inducing nonequilibrium spin polarization [5,6,7,8,9,10,11] tunable by local electric fields. Here we show that magnetization of a ferromagnet can be reversibly manipulated by the SO-induced polarization of carrier spins generated by unpolarized currents. Specifically, we demonstrate domain rotation and hysteretic switching of magnetization between two orthogonal easy axes in a model ferromagnetic semiconductor.In crystalline materials with inversion asymmetry, intrinsic spin-orbit interactions (SO) couple the electron spin with its momentumhk. The coupling is given by the Hamiltonian H so =h 2σ · Ω(k), whereh is the Planck's constant andσ is the electron spin operator (for holesσ should be replaced by the total angular momentum J). Electron states with different sign of the spin projection on Ω(k) are split in energy, analogous to the Zeeman splitting in an external magnetic field. In zinc-blende crystals such as GaAs there is a cubic Dresselhaus term[12] Ω D ∝ k 3 , while strain introduces a term Ω ε = C∆ε(k x , −k y , 0) that is linear in k, where ∆ε is the difference between strain in theẑ andx,ŷ directions [13]. In wurzite crystals or in multilayered materials with structural inversion asymmetry there also exists the Rashba term[14] Ω R which has a different symmetry with respect to the direction of k,, whereẑ is along the axis of reduced symmetry. In the presence of an electric field the electrons acquire an average momentumh∆k(E), which leads to the generation of an electric current j =ρ −1 E in the conductor, whereρ is the resistivity tensor. This current defines the preferential axis for spin precession Ω(j) . As a result, a nonequilibrium current-induced spin polarization J E Ω(j) is generated, whose magnitude J E depends on the strength of various mechanisms of momentum scattering and spin relaxation [5,15]. This spin polarization has been measured in non-magnetic semiconductors using optical [7,8,9,11,16] and electron spin resonance [17] techniques. It is convenient to parameterize J E in terms of an effective magnetic field H so . Different contributions to H so have different current dependencies (∝ j or j 3 ), as we...

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“…According to this model, the Fermi energy lies within the SC VB and is determined by the hole carrier density. 41,[58][59][60] Competing with this hypothesis, the impurity-band model predicts that the Fermi level resides inside the Mn impurity band detached from the GaAs VB. [14][15][16][61][62][63] In this case, the ferromagnetism spreads within this impurity band by a hopping effect without affecting the VB holes.…”

Section: Moke Spectramentioning

confidence: 99%

Magneto-optical Kerr spectroscopy of (Ga,Mn)(As,P) ferromagnetic layers: Experiments and k.p theory

Yahyaoui

Riahi

Maaref

et al. 2017

Journal of Applied Physics

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We present a theoretical and experimental study of the magneto-optical properties of thin (Ga,Mn) (As,P) layers on GaAs substrates with varying phosphorus fractions. Using a 40-band k.p model as well as an antiferromagnetic (s, p)-d exchange interaction, we calculate the dielectric tensor, the Kerr rotation angle, and the ellipticity in the interband transition region. Our calculations are validated through a set of accurate comparisons with experimental results. The Kerr ellipticity peak is found to be 2 to 3 times larger than the Kerr rotation angle both experimentally and theoretically. This work will enable to optimize the magneto-optical effects in these layers for maximum sensitivity in ultra-fast magnetization dynamics and domain microscopy experiments. Published by AIP Publishing.

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Exchange-Mediated Anisotropy of (Ga,Mn)As Valence-Band Probed by Resonant Tunneling Spectroscopy

Cited by 26 publications

References 17 publications

Recent progress in III-V based ferromagnetic semiconductors: Band structure, Fermi level, and tunneling transport

Recent progress in III-V based ferromagnetic semiconductors: Band structure, Fermi level, and tunneling transport

Evidence for reversible control of magnetization in a ferromagnetic material by means of spin–orbit magnetic field

Magneto-optical Kerr spectroscopy of (Ga,Mn)(As,P) ferromagnetic layers: Experiments and k.p theory

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