Related papers: Interaction effects and the metallic phase in p-Si…
Magnetoresistance results are presented for p-SiGe samples on the metallic side of the B=0 metal-insulator transition. It was possible to separate the weak localisation and Zeeman interaction effects but the results could not be explained…
We report on the results of investigation the conductivity and magnetoresistance (MR) temperature dependencies for the two strained multilayer p-type Ge/Ge_{1-x}Si_x heterostructures. The usual logarithmic temperature dependencies for zero…
The low-temperature resistivity of a SiGe 2-dimensional hole gas has been studied using the gate controlled carrier density as a parameter. A metal-insulator transition is seen both in the temperature and in the electric field behaviour.…
We find that temperature dependent screening can quantitatively explain the metallic behaviour of the resistivity on the metallic side of the so-called metal-insulator transition in p-SiGe. Interference and interaction effects exhibit the…
Magnetoresistivity measurements on p-type Si/SiGe quantum wells reveal the coexistence of a metallic behavior and weak localization. Deep in the metallic regime, pronounced weak localization reduces the metallic behavior around zero…
Magnetoresistance measurements are presented for a strained p-SiGe quantum well sample where the density is varied through the B=0 metal-insulator transition. The close relationship between this transition, the high field Hall insulator…
We present calculations of the spin and phase relaxation rates in GaAs/AlGaAs $p$-type quantum wells. These rates are used to derive the temperature dependence of the weak-localization correction to the conductivity. In $p$-type quantum…
At low temperature and for finite spin scattering in a weakly disordered metal, for a certain value, predicted from our theory, of the material-dependent paramagnon interaction, the total conductivity becomes highly sensitive to the orbital…
Observations are reported of a metal-insulator transition in a 2D hole gas in asymmetrically doped strained SiGe quantum wells. The metallic phase, which appears at low temperatures in these high mobility samples, is characterised by a…
A detailed investigation of the metallic behaviour in high quality GaAs-AlGaAs two dimensional hole systems reveals the presence of quantum corrections to the resistivity at low temperatures. Despite the low density ($r_{s}>10$) and high…
Shubnikov-de Haas data is presented for a p-SiGe sample exhibiting strongly insulating behaviour at nu = 3/2. In addition to the fixed points defining a high field metal- insulator transition into this phase separate fixed points can also…
We have studied temperature dependence of both diagonal and Hall resistivity in the vicinity of $\nu=1/2$. Magnetoresistance was found to be positive and almost independent of temperature: temperature enters resistivity as a logarithmic…
We compare the temperature dependence of resistivity \rho(T) of Si MOSFETs with the recent theory by Zala et al. This comparison does not involve any fitting parameters: the effective mass m* and g*-factor for mobile electrons have been…
A metal-insulator transition was induced by in-plane magnetic fields up to 27 T in homogeneously Sb-doped Si/SiGe superlattice structures. The localisation is not observed for perpendicular magnetic fields. A comparison with…
We report the results of an experimental study of the magnetoresistance $\rho_{xx}$ in two samples of $p$-Si/SiGe/Si with low carrier concentrations $p$=8.2$\times10^{10}$ cm$^{-2}$ and $p$=2$\times10^{11}$ cm$^{-2}$. The research was…
Universality of the extraordinary Hall effect scaling was tested in granular three-dimensional Ni-SiO2 films across the metal-insulator transition. Three types of magnetotransport behavior have been identified: metallic, weakly insulating…
We calculate the temperature, density, and parallel magnetic field dependence of low temperature electronic resistivity in 2D high-mobility Si/SiGe quantum structures, assuming the conductivity limiting mechanism to be carrier scattering by…
The nonlinear behavior of the Hall resistivity at low magnetic fields in single quantum well GaAs/In$_x$Ga$_{1-x}$As/GaAs heterostructures with degenerated electron gas is studied. It has been found that this anomaly is accompanied by the…
We show that in dilute metallic p-SiGe heterostructures, magnetic field can cause multiple quantum Hall-insulator-quantum Hall transitions. The insulating states are observed between quantum Hall states with filling factors \nu=1 and 2 and,…
We have studied the strongly interacting, two-valley two-dimensional (2D) electron system in ultrahigh mobility SiGe/Si/SiGe quantum wells in parallel magnetic fields strong enough to completely polarize the electron spins thus making the…