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Thillosen, N.; Cabañas, S.; Kaluza, N.; Guzenko, Vitaliy A.; Hardtdegen, H.; Schäpers, Thomas

doi:10.1103/physrevb.73.241311

Cited by 57 publications

(50 citation statements)

References 29 publications

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“…The zero field spin splitting energy for two studied samples equals to 0.23 and 0.35 meV. These values are comparable with those obtained by other groups for GaN/AlGaN heterostructures [7][8][9][10], but also are close to spin splitting in GaAs based heterostructures, where definitely both, bulk and structure inversion asymmetry are present [11]. The origin of such a large spin splitting in GaN/AlGaN could be revealed when bulk and structure inversion asymmetry contributions could be separated.…”

Section: Resultssupporting

confidence: 76%

Zero Field Spin Splitting in GaN/AlGaN Heterostructures Probed by the Weak Antilocalization

2008

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We present the magnetoconductivity measurements of a high mobility two-dimensional electron gas confined at GaN/AlGaN interface. The sensitive measurements of low field conductivity revealed both quantum corrections, the weak localization and antilocalization effects. It indicates the importance of the spin-orbit coupling in this wide band gap material. The analysis of the data provided the information about the temperature dependence of the dephasing time and total spin-orbit relaxation time. The conduction band spin splitting energy amounts to 0.23 meV and 0.35 meV at electron densities 2.2 × 10 12 cm −2 and 5.7 × 10 12 cm −2 , respectively.

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Section: Resultssupporting

confidence: 76%

Zero Field Spin Splitting in GaN/AlGaN Heterostructures Probed by the Weak Antilocalization

2008

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“…8 These terms have not been measured independently in the wurtzite system. Moreover, recent experiments based on Shubnikov-de Haas (SdH), 9,10 weak antilocalization (WAL), 11,12,13 and circular photogalvanic 14 measurements have given conflicting results for the spin splitting in wurtzite AlGaN/GaN heterostructures. In particular, spin-splitting energies extracted from the beat pattern of SdH measurements are found to be as large as 9 meV, which is about an order of magnitude larger than the theoretical estimates based on the Rashba coupling mechanism for this material system.…”

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confidence: 99%

“…Qualitatively, these results are consistent with the recent WAL measurements performed on a similar AlGaN/GaN heterostructure with a 2DEG. [11][12][13] However, the size of the WAL feature Thillosen et al…”

mentioning

confidence: 99%

“…The magnitude of the phase coherence time is similar to that of other III-V semiconductors measured in the same temperature range. 13,26 In the limited temperature range of these measurements, the phase coherence rate scales 1 τ φ = T 1.35 . Theories based on electronelectron interactions predict the phase coherence rate to scale linearly and quadratically with temperature at low and high temperatures, respectively.…”

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confidence: 99%

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Weak antilocalization and zero-field electron spin splitting inAlxGa1−xN∕AlN∕GaNheterostructures with a polarization-induced two-dimen

et al. 2006

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Spin-orbit coupling is studied using the quantum interference corrections to conductance in AlGaN/AlN/GaN two-dimensional electron systems where the carrier density is controlled by the persistent photoconductivity effect. All the samples studied exhibit a weak antilocalization feature with a spin-orbit field of around 1.8 mT. The zero-field electron spin splitting energies extracted from the weak antilocalization measurements are found to scale linearly with the Fermi wavevector ( E SS = 2αk f ) with an effective linear spin-orbit coupling parameter α = 5.5 ×10 −13 eV ⋅ m. The spin-orbit times extracted from our measurements varied from 0.74 to 8.24 ps within the carrier density range of this experiment.PACS Numbers: 71.70.Ej, 73.20.Fz, 73.40 To help resolve these issues, we have performed WAL and SdH measurements on three Al x Ga 1-x N/AlN/GaN samples with different Al concentrations. We used the persistent photoconductivity effect to vary the carrier density of the two-dimensional electron gas (2DEG). 18 The electron spin splitting energies extracted from our weak antilocalization Magnetoresistance and Hall measurements were performed in a variable temperature cryostat with a base temperature of 1.6 K. The samples exhibited SdH oscillations and integer quantum Hall effect at high magnetic fields. As expected, the carrier density of the sample with the highest Al fraction (Sample C) had the highest carrier density. To change the carrier density of the samples, we have illuminated the top surface of the samples through the optical access port of the cryostat via a flashlight. After each illumination the carrier density of the sample increases and does not drop to its equilibrium concentration, unless the sample is warmed up to room temperature. 20 By using the persistent photoconductivity effect we were able to vary the carrier density of 5 the samples in a controllable manner over the ranges of 0.8-1.3 ×10 12 cm -2 , 1.7-4.9 ×10 12 cm -2 , and 3.1-6.7 ×10 12 cm -2 for samples A, B, and C, respectively. Sample B had the highest electron mobility of µ = 20,300 cm 2 /V ⋅ s at a carrier concentration of n = 4.9 ×10 12 cm -2 . Consistent with previous studies based on gated structures, at low carrier densities the electron mobility is found to be decreasing with decreasing carrier density. 21 Typical high field magnetoresistivity traces obtained from these three samples are shown in Fig. 1. From the temperature dependence of SdH oscillations, we extracted an effective electron mass of m * = 0.23m e . We could not resolve any beat feature in the SdH oscillations even at high carrier densities where the onset of SdH is around 2 Tesla.The SdH oscillations also indicate that only a single subband of the quantum well is occupied by the 2DEG. Furthermore, at high carrier densities, we could resolve SdH oscillations corresponding to filling fractions above 100 which implies that the carrier density was uniform throughout our device even after illumination.The absence of any beat feature in the SdH oscillations prevented u...

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“…[14][15][16][17][18][19] On the other hand, is a quantity of great importance for the analysis of the transport in semiconductor samples, because it sets the scale of the transition between quantum and classical behaviors. Also, it provides information about the microscopic interactions among electrons and among electrons and phonons.…”

Section: Introductionmentioning

confidence: 99%

Electron dephasing scattering rate in two-dimensional GaAs/InGaAs heterostructures with embedded InAs quantum dots

Pagnossin

Meikap

Quivy

et al. 2008

Journal of Applied Physics

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We report a comprehensive study of weak-localization and electron-electron interaction effects in a GaAs/InGaAs two-dimensional electron system with nearby InAs quantum dots, using measurements of the electrical conductivity with and without magnetic field. Although both the effects introduce temperature dependent corrections to the zero magnetic field conductivity at low temperatures, the magnetic field dependence of conductivity is dominated by the weak-localization correction. We observed that the electron dephasing scattering rate τφ−1, obtained from the magnetoconductivity data, is enhanced by introducing quantum dots in the structure, as expected, and obeys a linear dependence on the temperature and elastic mean free path, which is against the Fermi-liquid model.

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Weak antilocalization in gate-controlledAlxGa1−xN∕GaNtwo-dimensiona

Cited by 57 publications

References 29 publications

Zero Field Spin Splitting in GaN/AlGaN Heterostructures Probed by the Weak Antilocalization

Zero Field Spin Splitting in GaN/AlGaN Heterostructures Probed by the Weak Antilocalization

Weak antilocalization and zero-field electron spin splitting inAlxGa1−xN∕AlN∕GaNheterostructures with a polarization-induced two-dimen

Electron dephasing scattering rate in two-dimensional GaAs/InGaAs heterostructures with embedded InAs quantum dots

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