Hydrogen Control of Ferromagnetism in a Dilute Magnetic Semiconductor

Goennenwein, Sebastian T. B.; Wassner, Thomas A.; Huebl, Hans; Brandt, Martin S.; Philipp, J. B.; Opel, Matthias; Gross, Rudolf; Koeder, A.; Schoch, W.; Waag, A.

doi:10.1103/physrevlett.92.227202

Cited by 77 publications

(72 citation statements)

References 27 publications

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“…However, it is now possible to control the density of carriers by chemical hydrogenation of the samples. 18,36 In this process, it is believed that the density of Mn and the density of defects Mn I do not change. Therefore, if interstitial Mn I defects were the main source of reducing the bulk magnetization m(0), one would expect m(0) to remain the same for all these hydrogenated samples.…”

Section: Realistic Couplings: the Case Of Gamnasmentioning

confidence: 98%

Superexchange induced canted ferromagnetism in dilute magnets

Bouzerar

Cepas³

2007

Phys. Rev. B

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We argue, in contrast to recent studies, that the antiferromagnetic superexchange coupling between nearest neighbour spins does not fully destroy the ferromagnetism in dilute magnets with long-ranged ferromagnetic couplings. Above a critical coupling, we find a canted ferromagnetic phase with unsaturated moment. We have calculated the transition temperature using a simplified local Random Phase Approximation procedure which accounts for the canting. For the dilute magnetic semiconductors, such as GaMnAs, using ab-initio couplings allows us to predict the existence of a canted phase and provide an explanation to the apparent contradictions observed in experimental measurements. Finally, we have compared with previous studies that used RKKY couplings and reported non-ferromagnetic state when the superexchange is too strong. Even in this case the ferromagnetism should remain essentially stable in the form of a canted phase.

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Section: Realistic Couplings: the Case Of Gamnasmentioning

confidence: 98%

Superexchange induced canted ferromagnetism in dilute magnets

Bouzerar

Cepas³

2007

Phys. Rev. B

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“…However, it is not trivial to quantify the effect of a given annealing procedure on the density of defects. More recently, the addition of hydrogen to the epilayer has been used to change GaMnAs magnetization properties [9,10]. In this latter case, it is possible to quantify the creation of defects by estimating the amount of hydrogen aggregated to GaMnAs.…”

Section: Introductionmentioning

confidence: 99%

Ion-beam modification of the magnetic properties ofGa1−xMnxAsepilayers

et al. 2010

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We study the controlled introduction of defects in GaMnAs by irradiating the samples with energetic ion beams, which modify the magnetic properties of the DMS. Our study focuses on the low-carrier-density regime, starting with as-grown GaMnAs films and decreasing even further the number of carriers, through a sequence of irradiation doses. We did a systematic study of magnetization as a function of temperature and of the irradiation ion dose. We also performed insitu room temperature resistivity measurements as a function of the ion dose. We observe that both magnetic and transport properties of the samples can be experimentally manipulated by controlling the ion-beam parameters. For highly irradiated samples, the magnetic measurements indicate the formation of magnetic clusters together with a transition to an insulating state. The experimental data are compared with mean-field calculations for magnetization. The independent control of disorder and carrier density in the calculations allows further insight on the individual role of this two factors in the ion-beam-induced modification of GaMnAs.

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“…The values given in Tables I and II show that the results achieved for the most stable complex (ab-Mn) do not agree with the experimental fi ndings. In particular, the theoretical results do not agree with a measured vibrational frequency of 2143 cm −1 and a total magnetization of 5 µ B , [3,5] see Table II. On the other hand, the H complexes that could agree with the experiment, e.g., the linear bc-As(Mn), are much higher in energy than the ab-Mn one.…”

Section: P Giannozzi Et Almentioning

confidence: 76%

“…[3,4] Magnetization measurements show that as-grown Mn x Ga 1−x As fi lms are ferromagnetic whereas they are found to be paramagnetic after hydrogenation. [5] Moreover, electronic transport measurements indicate that the density of the free holes is signifi cantly reduced by hydrogenation. The interest for the properties of hydrogenated DMS is motivated by the effects H generally has on the properties of IV and III-V semiconductors.…”

Section: Introductionmentioning

confidence: 99%

Theory of hydrogen complexes in Mn xGa1-xAs dilute magnetic semiconductors

Giannozzi¹,

Filippone²,

Bonapasta³

2006

Braz. J. Phys.

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Atomic hydrogen diffuses in semiconductor lattices and binds to impurities by forming complexes that can lead to a full neutralization of the impurity effects. In the present paper, the structural, vibrational, electronic and magnetic properties of complexes formed by H in the Mn x Ga 1−x As (x=0.03) dilute magnetic semiconductor have been investigated by using fi rst-principles DFT-LSD and LDA+U theoretical methods. The results account for recent experimental fi ndings showing a H passivation of the electronic and magnetic properties of Mn in GaAs. Moreover, they show that electron correlation has crucial effects on the properties of H-Mn complexes.

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Hydrogen Control of Ferromagnetism in a Dilute Magnetic Semiconductor

Cited by 77 publications

References 27 publications

Superexchange induced canted ferromagnetism in dilute magnets

Superexchange induced canted ferromagnetism in dilute magnets

Ion-beam modification of the magnetic properties ofGa1−xMnxAsepilayers

Theory of hydrogen complexes in Mn xGa1-xAs dilute magnetic semiconductors

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