Related papers: Thermally Activated Deviations from Quantum Hall P…
In a high mobility two-dimensional electron system in Si, near the critical density, $n_c=0.32\times10^{11}$cm$^{-2}$, of the apparent metal-to-insulator transition, the conductivity displays a linear temperature ($T$) dependence around the…
Magneto-transport measurements in a clean two-dimensional electron system confined to a wide GaAs quantum well reveal that, when the electrons occupy two electric subbands, the sequences of fractional quantum Hall states observed at high…
The dynamical transport properties near the integer quantum Hall transition are investigated at zero temperature by means of the Dirac fermion approach. These properties have been studied experimentally at low frequency omega and low…
The scaling behavior of the quantum phase transition from an insulator to a quantum Hall plateau state has often been examined within systems realizing Landau levels. We study the topological transition in energy band models with nonzero…
We calculate the temperature dependence of conductivity due to interaction correction for a disordered itinerant electron system close to a ferromagnetic quantum critical point which occurs due to a spin density wave instability. In the…
The temperature dependence of the magneto-conductivity in graphene shows that the widths of the longitudinal conductivity peaks, for the N=1 Landau level of electrons and holes, display a power-law behavior following $\Delta \nu \propto…
Optical Hall conductivity $\sigma_{xy}(\omega)$ is measured from the Faraday rotation for a GaAs/AlGaAs heterojunction quantum Hall system in the terahertz frequency regime. The Faraday rotation angle ($\sim$ fine structure constant $\sim$…
We report low temperature magnetotransport measurements on a high mobility (\mu=325,000 cm^2/V sec) 2D electron system on a H-terminated Si(111) surface. While low magnetic field data indicate a six-fold valley degenerate system, we observe…
We study the charge transport of the noninteracting electron gas in a two-dimensional quantum Hall system with Anderson-type impurities at zero temperature. We prove that there exist localized states of the bulk order in the…
For unpolarized electrons in a clean quantum wire, density functional theory reveals a thermally activated suppression of conductance. The activation temperature T_A grows slowly (roughly quadratically) with gate voltage due to pinning of…
We employ first-principles quantum field theoretical methods to investigate the longitudinal and transverse electrical conductivities of a strongly magnetized hot quantum electrodynamics (QED) plasma at the leading order in coupling. The…
We report the temperature($T$) and perpendicular magnetic field($B$) dependence of the Hall resistivity $\rho_{xy}(B)$ of dilute metallic two-dimensional(2D) holes in GaAs over a broad range of temperature(0.02-1.25K). The low $B$ Hall…
We present new results of the ``0.7'' 2(e^2)/h structure or quasi plateau in some of the most strongly confined point contacts so far reported. This strong confinement is obtained by a combination of shallow etching and metal gate…
The thermoelectric Hall effect is the generation of a transverse heat current upon applying an electric field in the presence of a magnetic field. Here we demonstrate that the thermoelectric Hall conductivity $\alpha_{xy}$ in the…
We report a new "dip" effect in the Hall resistance, R_{xy}, of a Si metal-oxide-semiconductor field-effect transistor in the quantum Hall effect regime. With increasing magnetic field, the Hall resistance moves from the plateau at Landau…
We measure the high magnetic field ($B$) microwave conductivity, Re$\sigma_{xx}$, of a high mobility 2D electron system containing an antidot array. Re$\sigma_{xx}$ vs frequency ($f$) increases strongly in the regime of the fractional…
We investigate finite temperature corrections to the Landauer formula due to electron-electron interaction within the quantum point contact. When the Fermi level is close to the barrier height, the interaction is strongly enhanced due to…
The temperature dependence of the conductance of a quantum point contact has been measured. The conductance as a function of the Fermi energy shows temperature-independent fixed points, located at roughly multiple integers of $e^{2}/h$.…
The longitudinal thermopower of ultra-high mobility two-dimensional electrons has been measured at both zero magnetic field and at high fields in the compressible metallic state at filling factor $\nu = 3/2$ and the incompressible…
Precision measurements of the Hall effect have been carried out for both archetypal heavy fermion compound - CeCu6 and exemplary solid solutions CeCu6-xAux (x= 0.1 and 0.2) with quantum critical behavior. The experimental results have been…