Electrical spin injection and detection at Al2O3/<i>n</i>-type germanium interface using three terminal geometry

Jain, A.; Louahadj, Lamis; Peiro, Julian; Breton, J. C. Le; Vergnaud, C.; Barski, A.; Beigné, C.; Notin, L.; Marty, A.; Baltz, Vincent; Auffret, S.; Augendre, E.; Jaffrès, Henri; George, Jean-Marie; Jamet, M.

doi:10.1063/1.3652757

Cited by 65 publications

(93 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Electrical spin injection and extraction in Ge have been recently investigated in lateral spin-transport devices with various doping profiles using nonlocal 19 and local [20][21][22][23][24][25] Hanle measurements, as well as in heterostructure and nanostructure devices. 26,27 Similar to direct band-gap semiconductors, optical orientation is an additional viable tool to investigate spin properties of electrons and holes in Ge.…”

Section: -18mentioning

confidence: 99%

Intrinsic spin lifetime of conduction electrons in germanium

2012

View full text Add to dashboard Cite

We investigate the intrinsic spin relaxation of conduction electrons in germanium due to electronphonon scattering. We derive intravalley and intervalley spin-flip matrix elements for a general spin orientation and quantify the resulting anisotropy in spin relaxation. The form of the intravalley spinflip matrix element is derived from the eigenstates of a compact spin-dependent k·p Hamiltonian in the vicinity of the L point (where thermal electrons are populated in Ge). Spin lifetimes from analytical integrations of the intravalley and intervalley matrix elements show excellent agreement with independent results from elaborate numerical methods.

show abstract

Section: -18mentioning

confidence: 99%

Intrinsic spin lifetime of conduction electrons in germanium

2012

View full text Add to dashboard Cite

show abstract

“…This three-terminal device used in non-local geometry represents a simple and unique tool to probe spin accumulation both into interface states and in the SC channel. 4,9,19 In particular, we could measure spin injection in the silicon and germanium conduction bands at room temperature. 20,22 The spin Hall angle (θ SHE , ratio between the transverse spin current density and the longitudinal charge current density) 23 is a key material parameter to develop new kinds of devices based on the spin Hall effect (SHE).…”

Section: Introductionmentioning

confidence: 99%

“…[4][5][6][7] Germanium exhibits the same crystal inversion symmetry as Si, a low concentration of nuclear spins but higher carrier mobility and larger spin-orbit coupling which should allow in principle spin manipulation by electric fields such as the Rashba field. [8][9][10][11][12] So far in order to perform spin injection from a ferromagnetic metal (FM) into Si or Ge, one needs to overcome at least three major obstacles: (i) the conductivity mismatch which requires the use of a highly-resistive spin-conserving interface between the FM and the SC, 13 (ii) the Fermi level pinning at the SC surface due to the presence of a high density of interface states and the interface spin flips which are generally associated 4,9,14 and finally (iii) the presence of random magnetic stray fields created by surface magnetic charges at rough interface 9,15 around which the electrically injected spins are precessing and partly lost by decoherence. In this work, we have inserted a thin MgO tunnel barrier between Ge and the CoFeB ferromagnetic electrode in order to: (i) circumvent the conductivity mismatch and (ii) partly alleviate Fermi level pinning by strongly reducing the interface states density [16][17][18] which leads to a modest Schottky barrier height at the MgO/n-Ge interface.…”

Section: Introductionmentioning

confidence: 99%

Spin pumping and inverse spin Hall effect in germanium

et al. 2013

Self Cite

View full text Add to dashboard Cite

We have measured the inverse spin Hall effect (ISHE) in n-Ge at room temperature. The spin current in germanium was generated by spin pumping from a CoFeB/MgO magnetic tunnel junction in order to prevent the impedance mismatch issue. A clear electromotive force was measured in Ge at the ferromagnetic resonance of CoFeB. The same study was then carried out on several test samples, in particular we have investigated the influence of the MgO tunnel barrier and sample annealing on the ISHE signal. First, the reference CoFeB/MgO bilayer grown on SiO 2 exhibits a clear electromotive force due to anisotropic magnetoresistance and anomalous Hall effect which is dominated by an asymmetric contribution with respect to the resonance field. We also found that the MgO tunnel barrier is essential to observe ISHE in Ge and that sample annealing systematically lead to an increase of the signal. We propose a theoretical model based on the presence of localized states at the interface between the MgO tunnel barrier and Ge to account for these observations. Finally, all of our results are fully consistent with the observation of ISHE in heavily doped n-Ge and we could estimate the spin Hall angle at room temperature to be ≈0.001.

show abstract

“…[23][24][25] as well as into Ge through MgO. [26][27][28][29][30][31][32][33][34] Among the latest experiments, the transformation of a spin-polarized electron current into left-or righthanded circularly polarized light in a spin light-emitting diode (spin LED) integrating a III-V semiconductor heterostructure 8,11,[13][14][15][16][17]19,23,34,35 is one of the most striking physical phenomena. The electric dipolar selection rules involved in a quantum well 36 (QW) embedded in a spin LED during electron-hole recombination require spin injection with an out-of-plane magnetization.…”

Section: Introductionmentioning

confidence: 99%

Spin injection at remanence into III-V spin light-emitting diodes using (Co/Pt) ferromagnetic injectors

et al. 2012

Self Cite

View full text Add to dashboard Cite

We have studied the perpendicular magnetic anisotropy of Co/Pt multilayers and the electron spin injection efficiency by optical spectroscopy from a [Co(0.6 nm)/Pt(1 nm)] 4 /Fe(0.3 nm)/MgO perpendicular tunnel spin injector grown on AlGaAs/GaAs semiconductor light-emitting diodes. We observe a 2.5% circular polarization at low temperature close to the magnetic remanence when the 0.3 nm Fe film of the ferromagnetic injector is sufficiently thin to maintain the magnetization out of plane. The acquired squared magnetization cycle is explained by the remaining interlayer exchange coupling existing between Fe and the (Co/Pt) multilayer through Pt or possible perpendicular magnetic anisotropy at the MgO/Fe interface. The corresponding spin polarization of the current is then estimated as 7%, measured by photoluminescence techniques, after the necessary uprenormalization, taking into account the electron spin-flip rate in the quantum well. In contrast, no circular polarization is observed when the thin Fe layer is removed and despite the rather high magnetic polarizability of the 5d 9 electronic open shell of Pt at the interface with MgO. This emphasizes the reduced size of tunneling branching of wave functions at the interface, of the order of the atomic plane unit.

show abstract

Electrical spin injection and detection at Al2O3/n-type germanium interface using three terminal geometry

Cited by 65 publications

References 21 publications

Intrinsic spin lifetime of conduction electrons in germanium

Intrinsic spin lifetime of conduction electrons in germanium

Spin pumping and inverse spin Hall effect in germanium

Spin injection at remanence into III-V spin light-emitting diodes using (Co/Pt) ferromagnetic injectors

Contact Info

Product

Resources

About