Effect of exchange electron-electron interaction on conductivity of InGaAs single and double quantum wells in ballistic regime

We report an experimental study of quantum conductivity corrections for two-dimensional electron gas in a GaAs/InGaAs/GaAs single and double quantum wells in a wide temperature range (1.8-100) K. We perform a comparison of our experimental data for the longitudinal conductivity at zero magnetic field to the theory of interaction-induced corrections to th transport coefficients. In the temperature range from 10 K up to (45-60) K, wich covers the ballistic interaction regimes for our samples, a rather good agreement between the theory and our experimental results has been found

Temperature dependence of quantum lifetime in n-InGaAs/GaAs structures with strongly coupled double quantum wells

Longitudinal ρxx(B) and Hall ρxy(B) magnetoresistances are experimentally investigated as a function of in-plane and transverse magnetic fields in n-InGaAs/GaAs nanostructures with strongly-coupled double quantum wells in the temperature range T = 1.8-70 K and magnetic fields B = 0-9.0 T. Experimental data on the temperature dependence of quantum lifetime in diffusive (kBT/τtr ≪ 1) and ballistic (kBT/τtr ≫ 1) regimes are reported. It has been found that in the ballistic regime in the temperature range where kBT/EF < 0.1, the observed quadratic temperature dependence of quantum lifetime is determined by inelastic electron-electron scattering. However, the temperature dependence of quantum lifetime cannot be quantitatively described by the existing theories in the whole temperature range. © 2013 American Institute of Physics

Tunneling effects in tilted magnetic fields in n-InGaAs/GaAs structures with strongly coupled double quantum wells

The effects of tunneling between two parallel two-dimensional electron gases in n-InGaAs/GaAs nanostructures with strongly coupled double quantum wells with a change in the in-plane component of a tilted magnetic field (up to Bnorm of matrix = 9.0 T) in the temperature range T = 1.8-70.0 K are investigated. A nonmonotonic temperature dependence of the inverse quantum lifetime τq -(T) is obtained from analysis of the dependence of the longitudinal resistance on the parallel component of the tilted magnetic field at fixed temperatures, ρxx(Bnorm of matrix, T). The quadratic portion of this dependence is found to be due to the contribution of inelastic electron-electron scattering. The decrease in the inverse quantum lifetime τq -(T) at T &gt; 0.1T F cannot be described within known theories; it seems, it is not related to the processes of electron momentum relaxation. © 2013 Pleiades Publishing, Ltd

Phenomenological features of mortality and morbidity dynamics in Tomsk versus heliogeophysical activity

The influence of heliogeophysical activity on the morbidity and mortality of the population in Tomsk is studied epidemiologically on the basis of regional data. The biological effectiveness of heliogeophysical factors selected on the basis of the Karhunen–Loeve method from epidemiological data on the morbidity and mortality in Tomsk in 1990–2008 is estimated. An analysis of the impact of variations in heliogeophysical activity on morbidity and mortality (according to the International Statistical Classification of Diseases and Related Health, ICD-10) showed the existence of common factors within different nosological classes that reliably correlate with the major components of variations in characteristic indices of heliogeophysical activity

Quasiclassical calculations of Landau level spectrum for 20.5-nm-wide H gTe quantum well: "extremum loop" model and effects of cubic symmetry

Quasiclassical calculations of the effective cyclotron mass and the spectrum of Landau levels have been carried out for carriers of the size-quantized H2 subband with a nonmonotonic dispersion law, which forms a valence band of 20.5-nm-wide HgTe quantum well with an inverted band structure. The model of the so-called "extremum loop", previously developed by Rashba and Sheka for semiconductors with a wurtzite lattice, has been used for calculations. The results obtained are compared both with the empirical picture and with quantum-mechanical calculations of the Landau level spectrum for the HgTe quantum well in the semimetallic phase. © 2021 Author(s).The research was carried out within the state assignment of Ministry of Science and Higher Education of the Russian Federation (theme “Electron” No. AAAA-A18-118020190098-5), supported in part by RFBR, Project No. 18-02-00172. We are grateful to Novik E. G. for the contribution to the band structure calculations of the real 20 nm HgTe quantum well

Activation transport under quantum Hall regime in HgTe-based heterostructure

We have measured the temperature (2.9 K < T < 50 K) and magnetic field (0 T < B < 9 T) dependences of longitudinal and Hall resistivities for HgCdTe/HgTe/HgCdTe system with HgTe quantum well width of 20.3 nm. The activation analysis of the experimental magnetoresistivity traces has been used as a quantitative tool to probe inter-Landau level distances. The activation energies were determined from the temperature dependence of the longitudinal resistivity in the regions of quantized Hall plateaus (for the filling factors ν of 1, 2 and 3) and the indications of the large values of the g factor ≅ 30–75 were found

HgTe quantum wells with inverted band structure: Quantum Hall effect and the large-scale impurity potential

We report on the longitudinal and Hall resistivities of a HgTe quantum well with inverted energy spectrum (dQW = 20.3 nm) measured in the quantum Hall (QH) regime at magnetic fields up to 9 T and temperatures 2.9-50 K. The temperature dependence of the QH plateau-plateau transition (PPT) widths and of variable range hopping (VRH) conduction on the Hall plateaus are analyzed. The data are presented in a genuine scale form both for PPT regions and for VRH regime. Decisive role of the long-range random potential (the potential of remote ionized impurities) in the localization-delocalization processes in the QH regime for the system under study is revealed. © 2019 Author(s)