Anomalousk-dependent spin splitting in wurtziteAlxGa1−xN∕

Abstract

We have confirmed the k-dependent spin splitting in wurtzite Al x Ga 1-x N/GaN heterostructures. Anomalous beating pattern in Shubnikov-de Haas measurements arises from the interference of Rashba and Dresselhaus spin-orbit interactions. The dominant mechanism for the k-dependent spin splitting at high values of k is attributed to Dresselhaus term which is enhanced by the ∆ C1 -∆ C3 coupling of wurtzite band folding effect.

Rashba spin splitting for the first two subbands in heterostructures

“…The carrier concentration of each subband (including spin subband) and the difference of the energy minimum between different subbands can be obtained from SdH frequencies, and information on the magnitude of the spin splitting due to spin-orbit coupling can be obtained from the node positions of the characteristic beating pattern in the Shubnikov-de Haas oscillations [2,12,30,34,35]. Therefore, according to our calculation results, considering the occupation of electrons on the first two subbands and their spin splitting, there will be four periodicities of SdH oscillations.…”

“…More and more attention has been paid to the spin of electrons in semiconductors in order to develop semiconductor spintronic devices [1][2][3]. In systems with an inversion asymmetry of the crystal potential, the spin-orbit interaction lifts the spin degeneracy of the electron state at zero magnetic field [4].…”

Spin splitting in AlxGa1−xN/GaN quasiballistic quantum wires

“…The ratio of carrier concentration residing at GaN layer versus that at Al 0.18 Ga 0.82 N barrier is ͑7.025: 1͒, yielding n 2d = 6.88 ϫ 10 12 cm −2 at the heterointerface and 0.98ϫ 10 12 cm −2 at the Al 0.18 Ga 0.82 N barrier. Using the effective m ‫ء‬ = 0.215m 0 , 11 we calculated the Fermi level to be 76.6 meV above the first subband minimum, and its Fermi wave vector k F = 0.6575 nm −1 .…”

“…The Shubnikov-de Haas ͑SdH͒ oscillation shows a spin-degenerate Fermi surface at n 2d = 8.68 ϫ 10 12 cm −2 for x = 0.22, and a beating pattern appears with an increasing spin-splitting energy after the electron density is enhanced by persistent photoconductivity effect. 11 When a nanowire is made of Al x Ga 1−x N / GaN heterostructure and the width of the 2DEG channel is reduced to ballistic regime, the scattering of impurity and defect is eliminated in electron transport. The spin of electron state then follows quantummechanic transportation, beyond the diffusive transportation of classical Drude model.…”

Zero-field spin splitting in AlxGa1−xN/GaN heterostructures with various Al compositions

“…The spin-splitting energy had been observed linearly as a function of the Fermi wave vector by means of the persistent photoconductivity effect. 11,12 However, the spin-orbit coupling parameter ␣ did not change significantly in their experiments. From the viewpoint of the proposed device, the most important parameter, which governs the spin precession, is the spin-orbit coupling parameter ␣.…”