Dimensional Control of Antilocalization and Spin Relaxation in Quantum Wires

Kettemann, Stefan

doi:10.1103/physrevlett.98.176808

Cited by 108 publications

(159 citation statements)

References 21 publications

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“…The dependence of the non-local signal on the device geometry (length and width) can be obtained by solving the diffusion equation for the spins and is given by 31,35,36 …”

Section: Resultsmentioning

confidence: 99%

Giant spin Hall effect in graphene grown by chemical vapour deposition

et al. 2014

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Advances in large-area graphene synthesis via chemical vapour deposition on metals like copper were instrumental in the demonstration of graphene-based novel, wafer-scale electronic circuits and proof-of-concept applications such as flexible touch panels. Here, we show that graphene grown by chemical vapour deposition on copper is equally promising for spintronics applications. In contrast to natural graphene, our experiments demonstrate that chemically synthesized graphene has a strong spin-orbit coupling as high as 20 meV giving rise to a giant spin Hall effect. The exceptionally large spin Hall angle B0.2 provides an important step towards graphene-based spintronics devices within existing complementary metal-oxide-semiconductor technology. Our microscopic model shows that unavoidable residual copper adatom clusters act as local spin-orbit scatterers and, in the resonant scattering limit, induce transverse spin currents with enhanced skew-scattering contribution. Our findings are confirmed independently by introducing metallic adatoms-copper, silver and gold on exfoliated graphene samples.

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“…The dependence of the non-local signal on the device geometry (length and width) can be obtained by solving the diffusion equation for the spins and is given by 31,35,36 …”

Section: Resultsmentioning

confidence: 99%

Giant spin Hall effect in graphene grown by chemical vapour deposition

et al. 2014

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“…In fact, a variety of theoretical models are needed to appropriately characterize the differing nanowires. The WAL/WL effect in the diffusive regime was analyzed by Kettemann [32] and Wenk [33,34] for planar quantum wires with a zinc-blende lattice. In our preceding article [14], we developed a model for diffusive zinc-blende nanowires where the transport is governed by surface states, which occurs in materials with Fermi level surface pinning [12,25,30,35,36] or core/shell nanowires [26].…”

Section: Introductionmentioning

confidence: 99%

Magnetoconductance correction in zinc-blende semiconductor nanowires with spin-orbit coupling

et al. 2017

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We study the effects of spin-orbit coupling on the magnetoconductivity in diffusive cylindrical semiconductor nanowires. Following up on our former study on tubular semiconductor nanowires, we focus in this paper on nanowire systems where no surface accumulation layer is formed but instead the electron wave function extends over the entire cross section. We take into account the Dresselhaus spin-orbit coupling resulting from a zinc-blende lattice and the Rashba spin-orbit coupling, which is controlled by a lateral gate electrode. The spin relaxation rate due to Dresselhaus spin-orbit coupling is found to depend neither on the spin density component nor on the wire growth direction and is unaffected by the radial boundary. In contrast, the Rashba spin relaxation rate is strongly reduced for a wire radius that is smaller than the spin precession length. The derived model is fitted to the data of magnetoconductance measurements of a heavily doped back-gated InAs nanowire and transport parameters are extracted. At last, we compare our results to previous theoretical and experimental studies and discuss the occurring discrepancies.

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“…As can be seen in Fig. 4, the height of the conductance peak decreases by about a factor of 2, when the temperature is increased from 0.5 to 4.0 K. By fitting the experimental data points to the Kettemann model, 22 which is the appropriate model for wire structures, the phase-coherence length l and spin-relaxation length l so were extracted. In Fig.…”

mentioning

confidence: 99%

Spin-orbit coupling and phase-coherent transport in InN nanowires

Petersen¹,

Hernandez²,

Calarco³

et al. 2009

Phys. Rev. B

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The low-temperature quantum transport properties of gated InN nanowires were investigated. Magneticfield-dependent as well as gate-dependent measurements of universal conductance fluctuations were performed to gain information on the phase coherence in the electron transport. We found a pronounced decrease in the variance of the conductance by about a factor of 2 in gate-dependent fluctuation measurements if a magnetic field is applied. This effect is explained by the suppression of the Cooperon channel of the electron correlation contributing to the conductance fluctuations. Despite the fact that the diameter of the nanowire is less than 100 nm a clear weak antilocalization effect is found in the averaged magnetoconductance being in strong contrast to the suppression of weak antilocalization for narrow quantum wires based on planar two-dimensional electron gases. The unexpected robustness of the weak antilocalization effect observed here is attributed to the tubular topology of the surface electron gas in InN nanowires. DOI: 10.1103/PhysRevB.80.125321 PACS number͑s͒: 73.23.Ϫb, 72.15.Rn, 73.63.Nm Semiconductor nanowires fabricated by a bottom-up approach are not only interesting for the realization of future nanoscaled devices 1,2 but also appear to be very attractive model systems to tackle fundamental questions concerning the transport in strongly confined systems. [3][4][5] In order to avoid the problem connected with carrier depletion, narrowband gap semiconductors, i.e., InAs or InN, 1,6,7 are preferred. The underlying reason is that here the Fermi-level pinning in the conduction band results in a carrier accumulation at the surface. In fact, the tubular topology of the surface electron gas opens up the possibility to observe unconventional quantum transport phenomena. 7 When the phase-coherence length l in the nanowire is comparable to its dimensions the conductance fluctuates if a magnetic field is applied or if the electron concentration is changed by means of a gate electrode. [8][9][10] These so-called universal conductance fluctuations being in the order of e 2 / h originate from the fact that in small disordered samples, electron interference effects are not averaged out. 11,12 Here, we analyzed universal conductance fluctuations to study the quantum transport properties in InN nanowires. In contrast to previous investigations 6,7,9,10 the successful preparation of a top-gate electrode allowed us to study universal conductance fluctuations not only as a function of magnetic field but also as a function of gate voltage. Since InN is a narrow band gap semiconductor, one naturally expects spinorbit coupling effects similar to the case of InAs. 13 Because this phenomena is of importance for spin electronic applications, we devoted special attention to the open question if spin-orbit coupling is present in InN nanowires. In transport measurements information on the spin-orbit coupling can be gained from the analysis of the characteristic beating pattern in Shubnikov-de Haas oscillations 14 or by study...

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Dimensional Control of Antilocalization and Spin Relaxation in Quantum Wires

Cited by 108 publications

References 21 publications

Giant spin Hall effect in graphene grown by chemical vapour deposition

Giant spin Hall effect in graphene grown by chemical vapour deposition

Magnetoconductance correction in zinc-blende semiconductor nanowires with spin-orbit coupling

Spin-orbit coupling and phase-coherent transport in InN nanowires

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