Dephasing in (Ga,Mn)As Nanowires and Rings

Wagner, K.; Neumaier, Daniel; Reinwald, Matthias; Wegscheider, Werner; Weiss, Dieter

doi:10.1103/physrevlett.97.056803

Cited by 43 publications

(60 citation statements)

References 30 publications

(33 reference statements)

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“…Recent experiments on mesoscopic Ga 1−x Mn x As samples [31,32] estimate inelastic path lengths l in ∼ 100 nm for x = 0.02 at 10 mK and for x = 0.06 at 100 mK, respectively, and a dephasing time τ φ that varies inversely with temperature at higher temperatures (T < ∼ 1 K). This places our samples of thickness t = 120 nm in the 3D regime (wherein the film thickness exceeds the inelastic length l in ) in the temperature range of interest (100 mK≤ T ≤ 4 K).…”

Section: Quantum Corrections To the Longitudinal Conductivitymentioning

confidence: 99%

Localization and the anomalous Hall effect in a dirty metallic ferromagnet

2010

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We report magnetoresistance measurements over an extensive temperature range (0.1 K ≤ T ≤ 100 K) in a disordered ferromagnetic semiconductor (Ga1−xMnxAs). The study focuses on a series of metallic Ga1−xMnxAs epilayers that lie in the vicinity of the metal-insulator transition (kF le ∼ 1). At low temperatures (T < 4 K), we first confirm the results of earlier studies that the longitudinal conductivity shows a T 1/3 dependence, consistent with quantum corrections from carrier localization in a "dirty" metal. In addition, we find that the anomalous Hall conductivity exhibits universal behavior in this temperature range, with no pronounced quantum corrections. We argue that observed scaling relationship between the low temperature longitudinal and transverse resistivity, taken in conjunction with the absence of quantum corrections to the anomalous Hall conductivity, is consistent with the side-jump mechanism for the anomalous Hall effect. In contrast, at high temperatures (T > ∼ 4 K), neither the longitudinal nor the anomalous Hall conductivity exhibit universal behavior, indicating the dominance of inelastic scattering contributions down to liquid helium temperatures.

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Section: Quantum Corrections To the Longitudinal Conductivitymentioning

confidence: 99%

Localization and the anomalous Hall effect in a dirty metallic ferromagnet

2010

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“…To this class of effects belong universal conductance fluctuations (UCF) [10], the Aharonov-Bohm (AB) effect [11], weak localization (WL) [1], weak anti-localization (WAL) [1] and conductivity corrections due to electronelectron interactions (EEI) [12]. Recently the existence of AB oscillations in ferromagnetic rings was predicted theoretically [13] and subsequently observed in ferromagnetic Fe 19 Ni 81 - [14] and in (Ga,Mn)As-nanorings [15]. In (Ga,Mn)As the phase coherence length was extracted from UCFs in nanowires giving typical values between 90 nm and 300 nm at 20 mK [15,16].…”

mentioning

confidence: 99%

“…Recently the existence of AB oscillations in ferromagnetic rings was predicted theoretically [13] and subsequently observed in ferromagnetic Fe 19 Ni 81 - [14] and in (Ga,Mn)As-nanorings [15]. In (Ga,Mn)As the phase coherence length was extracted from UCFs in nanowires giving typical values between 90 nm and 300 nm at 20 mK [15,16]. This raises the question whether WL corrections -or WAL effects -can be observed in ferromagnetic (Ga,Mn)As, a material in which the spin-orbit (SO) interactions for holes in the valence band is quite strong.…”

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confidence: 99%

“…3a is quite nicely fitted by two parameters, the phase coherence length L φ and the spin orbit length L SO which is the characteristic length on which spin flip occurs due to SO interaction. L φ can be extracted independently from UCFs measured on individual 1D-wires [15,16], so that essentially only one free parameter prevails. To study UCFs we fabricated a single wire, w = 35 nm wide and L = 370 nm long, from the same material as sample 2 and 3 (sample 4 in Tab.…”

mentioning

confidence: 99%

“…3b. G(B) was measured in a perpendicular B -field from -3 T to 3 T for T between 20 mK and 1 K (for details see [15]). Corresponding data taken at 20 mK show pronounced, reproducible UCFs, displayed in Fig.…”

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Weak Localization in Ferromagnetic (Ga,Mn)As Nanostructures

et al. 2007

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We report on the observation of weak localization in arrays of (Ga,Mn)As nanowires at millikelvin temperatures. The corresponding phase coherence length L φ is typically between 100 nm and 200 nm at 20 mK. Strong spin-orbit interaction in the material is manifested by a weak anti-localization correction around zero magnetic field.PACS numbers: 73.43. Jn, 72.25.Dc, 73.43.Qt Quantum corrections to the resistance like weak localization are suppressed by a sufficiently strong perpendicular magnetic field B [1]. Hence the question arises whether such effects can be observed in ferromagnets which have an intrinsic magnetic induction. While few experimental works explored this problem [2,3], a definite experimental answer is still lacking. Hence, the advent of the new ferromagnetic semiconductor material (Ga,Mn)As with significantly smaller internal field compared to conventional ferromagnets offers a new opportunity to address such questions. Ferromagnetic semiconductors like (Ga,Mn)As [4] are interesting materials for spintronics as well, as they combine ferromagnetic properties with the versatility of semiconductors [5]. The spin 5 2 -Mn-ions on regular sites of the zinc-blende lattice of the GaAs host act as acceptors thus providing both holes and magnetic moments. The ferromagnetic order between the Mn-ions is mediated by these holes [6]. By now ferromagnetism in (Ga,Mn)As is well understood, allowing to predict Curie temperatures [6], magnetocrystalline anisotropies [7] as well as the anisotropic magnetoresistance effect [8]. In this respect (Ga,Mn)As is one of the best understood ferromagnetic materials at all [9] and hence suitable as a model system to study quantum corrections to the conductivity.

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Quantum Transport in Diluted Magnetic Semiconductors

Jaroszyński

2010

Introduction to the Physics of Diluted Magnetic Semiconductors

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Dephasing in (Ga,Mn)As Nanowires and Rings

Cited by 43 publications

References 30 publications

Localization and the anomalous Hall effect in a dirty metallic ferromagnet

Localization and the anomalous Hall effect in a dirty metallic ferromagnet

Weak Localization in Ferromagnetic (Ga,Mn)As Nanostructures

Quantum Transport in Diluted Magnetic Semiconductors

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