Effect of the heterointerface on the spin splitting in modulation doped InxGa1−xAs/InP quantum wells for B→0

Abstract

Spin splitting of conduction band electrons in In0.53Ga0.47As/In0.77Ga0.23As/InP heterostructures due to spin-orbit coupling is studied by performing Shubnikov–de Haas measurements on nongated and gated Hall bars. From an analysis of the beating pattern in the Shubnikov–de Haas oscillations, the spin-orbit coupling constant is determined. For a symmetric sample no beating pattern and thus no spin splitting is observed. This demonstrates that the k3 contribution to the spin-orbit coupling constant can be neglected. By applying an envelope function theory it is shown that the major contribution to the Rashba spin-orbit coupling originates from the band offset at the interface of the quantum well. Using gated Hall bar structures it is possible to alter the spin-orbit coupling by application of an appropriate gate voltage. A more negative gate voltage leads to a more pronounced asymmetry of the quantum well, which gives rise to a stronger spin-orbit coupling.

Magnetotransport in high-g-factor low-density two-dimensional electron systems confined inIn0.75Ga0.25Desrat1, Giazotto2, Pellegrini3 et al. 2004Phys. Rev. B354260View full textAdd to dashboardCite

“…An In x Al 1−x As step graded buffer with x ranging from 0.15 to 0.85 was inserted between the substrate and the 2DES to achieve almost complete strain relaxation at the quantum-well region. In these nominally undoped structures, a relatively low carrier concentration close to 3 × 10 11 cm −2 can be achieved and this confirms that there exists an intrinsic source of free carriers [15]. The origin of the doping is, however, still unclear.…”

“…Rashba coupling as shown in Ref. [15]) still maintaining large values of the electron mobility. In this case several recently predicted spin-related phenomena can be studied.…”

Theory of spin-orbit coupling at LaAlO3/SrTiO3interfaces and SrTiO3surfaces

“…This is because the assumption of nearly free 2DEG, which ignores the region of ion cores and the asymmetric feature of the interface wavefunction, is too simple. In reality, the expression for ∆ R is much more complicated [17][18][19][20][21] and usually treated as a fitting parameter in semiconductor heterostructures and metal surfaces.…”

Electronic and spin properties of Rashba billiards

“…Structural inversion asymmetry in semiconductor heterostructures has been shown [3] to give rise to a spin splitting of the same type as was discussed in an early paper by Rashba [4]. Its tunability by external gate voltages [5,6] has motivated the theoretical design of a spin-controlled field-effect transistor [7]. Novel spin properties arise from the interplay between Rashba spin splitting and further confinement of two-dimensional electrons in quantum wires [8,9,10,11] or dots [12,13,14,15,16,17].…”

“…[29].) π/k so is the spin-precession length, which can be tuned independently of the system size [5,6,7]. In the absence of any lateral confinement, the energy dispersion splits into two branches [28]:…”