Electron-spin resonance of the two-dimensional electron gas in Ga0.47In0.53As-InP heterostructures

Abstract

The microwave-induced change of the magnetoresistivity of Gao.47In0. 53As-InP heterostructures reveals resonant structure which is attributed to electron-spin resonance of the two-dimensional conduction electrons. With microwave frequencies up to 480 GHz and in magnetic fields up to 12 T, we studied the spin splitting of the two lowest Landau levels in different samples. The spin splitting of these Landau levels is a quadratic function of the magnetic field and its extrapolation to zero magnetic field leads to vanishing spin splitting. The g factors depend on the magnetic field 8 and the Landau level N as follows: g(B,iV) gse(N+ -, ' )8, where gQ and c are sample-dependent parameters, which are of the order of go=4. 1 and c=0.08 T ', in the studied heterostructures.Electron-spin resonance (ESR), detected in the resonant change of the magnetoresist'ivity p"", turned out to be a worthwhile method for the investigation of g factors of the two-dimensional electron systems in GaAs-Al"-Gal "As heterostructures' and also in GaAs-Gal "In"P heterostructures.Together with the effective mass m the g factor determines the energy spectrum of a twodimensional electron gas (2D EG) in a perpendicular magnetic field B:Here, Ei is the subband energy, e is the elementary charge, 5 is Planck's constant, and pe is Bohr's magneton. N 0, 1,2, . . . is the Landau-level index and m, is the magnetic spin quantum number that takes the values m, + -, ' ("spin up") and m, --, ' ("spin down").Both m and g are not constants, but depend on the magnetic field and the Landau quantum number. For the g factor in GaAs-Al"Gal -"As heterostructures, it is well known that this is mainly due to the nonparabolicity of the GaAs conduction band and only to a negligible extent due to spin-orbit coupling in the electric field at the interface. Furthermore, the g factor is mainly determined by the GaAs properties, and not by those of the barrier material, as the electronic wave function enters only slightly into the barrier. In the material combination used in this Rapid Communication, the electrons are on the GaQ47Ino 53As side of the interface and the InP acts as the barrier. Therefore, the spin splitting of the 2D EG is expected to depend mainly on the properties of the GaQ471no 53As and especially on its g factor. There is, however, no certainty about this value up to now. The g factor for Gal "In"As has been experimentally determined only for 0~x~0.1 (Ref. 5) and x l. s For x 0.53, a simple linear interpolation between g -0.44 for GaAs and g -14.7 for InAs yields a g factor of g -8.0. The interpretation of electrorefiectance data in terms of a three-band k p theory gave g -3.38, and the interpretation of interband magnetoabsorption data resulted in g -4.5 (Ref.8) for Gao.471nQ. 53As. These different calculations are completed by an optically detected magnetic resonance study on a 15-nm-thick Gao47InQ 53As quantum well, layered between InP barriers, 9 where the g factor turned out to be i g i 5.6+0.3 (at B=0.1 T) for the optically excited two-dimensional ...

Temperature dependence and mechanism of electrically detected ESR at theν=1filling factor of a two-dimensional electron system

“…It has been previously demonstrated that high sensitivity can be obtained if the ESR absorption is detected electrically via a change induced in the magnetoresistance that can be observed under certain conditions in the regime of the quantum Hall effect [2]. This method has been successfully used in the analysis of the magnetic field dependence of the bare electron g-factor [3,4,5], the electron-nuclear interaction and nuclear-spin relaxation rates as a function of magnetic field [6] and the g-factor dependence on the top-gate voltage [7]. Although a variety of applications of EDESR have been demonstrated in quantum Hall systems, there have been no previous reports describing the underlying physics of the electrical response to ESR transitions in a 2DES.…”

Magnetosubbands of semiconductor quantum wires with Rashba spin-orbit coupling

“…37 For the g factor a value of −4 was assumed. 38 The value of E F,2D was taken as the zero field value of the quantum wire Fermi energy E F,1D , which should be a good approximation for wire structures with a larger number of occupied levels. In principle, the carrier confinement in the wire can be characterized by the oscillator frequency 0 if a harmonic confinement potential is assumed.…”

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

“…Second, the bare g-factor is expected to be very large. For instance the bare gfactor measured by electron spin resonance was found at around -5 in In 0.53 Ga 0.47 As [3] while effective g-factors g * (renormalized by electron-electron interactions) with absolute values between 14 and 28 were recently suggested from magneto-transport data [4,5]. The large resulting Zeeman spin splitting under the application of weak magnetic fields makes this semiconductor system a promising candidate for spin-valve mesoscopic devices working at relatively high temperatures [6].…”