Weak Antilocalization Effect in an AlAs/AlGaAs Quantum Well

JETP Letters - Weak antilocalization in a narrow AlAs quantum well containing a two-dimensional electron system with a large effective mass at low temperatures has been studied. Such quantum...     

Electron paramagnetic resonance study of the nuclear spin dynamics in an AlAs quantum well

The nuclear spin dynamics in an asymmetrically doped 16-nm AlAs quantum well grown along the [001] direction has been studied experimentally using the time decay of the Overhauser shift of paramagnetic resonance of conduction electrons. The nonzero spin polarization of nuclei causing the initial observed Overhauser shift is due the relaxation of the nonequilibrium spin polarization of electrons into the nuclear subsystem near electron paramagnetic resonance owing to the hyperfine interaction. The measured relaxation time of nuclear spins near the unity filling factor is (530 ± 30) min at the temperature T = 0.5 K. This value exceeds the characteristic spin relaxation times of nuclei in GaAs/AlGaAs heterostructures by more than an order of magnitude. This fact indicates the decrease in the strength of the hyperfine interaction in the AlAs quantum well in comparison with GaAs/AlGaAs heterostructures.     

Renormalization of the Effective Electron Mass Governing the Period of Microwave-Induced Resistance Oscillations in ZnO/MgZnO Heterojunctions

The phenomenon of microwave-induced magnetoresistance oscillations is studied in a series of ZnO/MgZnO heterojunctions characterized by different two-dimensional electron densities n. It is found that the effective electron mass m* determined from the period of microwave-induced magnetoresistance oscillations depends essentially on this parameter. For high densities, the value of m* tends to the effective electron mass in bulk ZnO, while for low densities, m* increases pronouncedly and becomes considerably larger than the electron cyclotron mass. The experimental results give clear evidence of a significant impact of the electron–electron interaction on microwave-induced magnetoresistance oscillations.     

Contactless Observation of Microwave Induced Resistance Oscillations in ZnO/MgxZn1 – xO Heterojunction

JETP Letters - In high-quality ZnO/MgxZn1 – xO heterojunctions, microwave-induced magnetoresistance oscillations have been investigated using a contactless technique. The basic detection...     

Erratum to: Several Articles in JETP Letters

JETP Letters - An Erratum to this paper has been published: https://doi.org/10.1134/S0021364022350016     

Observation of Electron Spin Resonance in the Microwave-Induced Photovoltage

JETP Letters - The microwave-induced photovoltage in two-dimensional electron systems in an AlAs quantum well and a ZnO/MgZnO heterojunction under the conditions of the quantum Hall effect is...     

Spin relaxation in GaAs/AlGaAs quantum wells in the vicinity of odd filling factors

Electron spin resonance in GaAs/AlGaAs quantum wells in the vicinity of odd filling factors ν = 3, 5, and 7 is investigated. The spin relaxation time of two-dimensional electrons is determined from the width of the microwave resonance absorption line. Dependences of the spin relaxation time on the filling factor, temperature, and orientation of the magnetic field are investigated. The spin relaxation time decreases noticeably upon deviation from odd filling factors, and its maximum value depends on the angle between the magnetic field and the plane of the two-dimensional electron gas.     

Interface contributions to the spin-orbit interaction parameters of electrons at the (001) GaAs/AlGaAs interface

One-body mechanisms of spin splitting of the energy spectrum of 2D electrons in a one-side doped (001) GaAs/Al _x Ga_{1 ? x} As quantum well have been studied theoretically and experimentally. The interfacial spin splitting has been shown to compensate (enhance) considerably the contribution of the bulk Dresselhaus (Bychkov-Rashba) mechanism. The theoretical approach is based on the solution of the effective mass equation in a quasi-triangular well supplemented by a new boundary condition at a high and atomically sharp hetero-barrier. The model takes into account the spin-orbit interaction of electrons with both bulk and interfacial crystal potential having C _2v symmetry, as well as the lack of inversion symmetry and nonparabolicity of the conduction band in GaAs. The effective 2D spin Hamiltonian including both bulk and interface contributions to the Dresselhaus (α_BIA) and Rashba (α_SIA) constants has been derived. The analytical relation between these constants and the components of the anisotropic nonlinear g-factor tensor in an oblique quantizing magnetic field has been found. The experimental approach is based, on one hand, on the detection of electron spin resonance in the microwave range and, on the other hand, on photoluminescence measurements of the nonparabolicity parameter. The interface contributions to α_BIA and α_SIA have been found from comparison with the theory.     

Electron Spin Resonance under Conditions of a Ferromagnetic Phase Transition

JETP Letters - The spin resonance of two-dimensional conduction electrons in a ZnO/MgZnO heterojunction in tilted magnetic fields is studied near the filling factor $$\nu = 2$$ . The analysis of...     

Electron Spin Resonance in an AlAs Quantum Well near Filling Factor 1

JETP Letters - The phenomenon of spin resonance of two-dimensional electrons confined in a 16 nm AlAs quantum well is studied in the quantum Hall effect regime near filling factor 1. At a...