相关论文: Frequency dependent transport in the integer quant…
Frequency dependent electronic transport is investigated for a two-dimensional disordered system in the presence of a strong perpendicular static magnetic field. The ac-conductivity is calculated numerically from Kubo's linear response…
The status of the ac quantum Hall effect is reviewed with emphasis on the theoretical development in recent years. In particular, the numerical approaches for the calculation of the frequency dependent Hall and longitudinal conductivities…
We present high frequency measurements of the diagonal conductivity sigma_xx of a two dimensional electron system in the integer quantum Hall regime. The width of the sigma_xx peaks between QHE minima is analyzed within the framework of…
We consider the quantum Hall effect (QHE) in a system of interacting electrons. Our formalism is valid for systems in the presence of an external magnetic field, as well as for systems with a nontrivial band topology. That is, the…
The fractional quantum Hall effect (FQHE) is extensively studied, but the explanation for Hall plateau widths and excitation energy gaps remains elusive. We study the effective theory of FQHE built upon experimental inputs of Hall current…
The diagonal conductivity $\sigma_{xx}$ was measured in the Corbino geometry in both integer and fractional quantum Hall effect (QHE). We find that peak values of $\sigma_{xx}$ are approximately equal for transitions in a wide range of…
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…
Contrary to common belief, the current emitted by a contact embedded in a two-dimensional electron gas (2DEG) is quantized in the presence of electric and magnetic fields. This observation suggests a simple, clearly defined model for the…
We have measured the complex conductivity $\sigma_{xx}$ of a two-dimensional electron system in the quantum Hall regime up to frequencies of 6 GHz at electron temperatures below 100 mK. Using both its imaginary and real part we show that…
We determine wave number $q$ and frequency $\omega$ dependent spin Hall conductivity $\sigma_{yx}^s(q, \omega)$ for a disordered two dimensional electron system with Rashba spin orbit interaction when $\q$ is {\it transverse} to the…
High frequency (hf) conductivity in the form $\sigma^{hf} = \sigma_1^{hf} - i\sigma_2^{hf}$ was obtained from the measurement of Surface Acoustic Waves (SAW) attenuation and velocity (f=30 MHz) in GaAs/AlGaAs heterostructures ($n=1.3-7\cdot…
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 investigated the Integer Quantum Hall Effect (IQHE) using an inductive method. The following conclusions can be derived from our study: (i) when the Fermi energy is located between Landau levels the only extended states at the Fermi…
Dynamical Hall conductivity {\sigma}_H({\omega}) of a 2D electron gas with impurities in the perpendicular magnetic field is analyzed. Plateau-like behavior at low frequencies as well as at high frequencies provided the complete filling of…
Energy spectrum of fractional quantum Hall (FQH) states is composed of single electron energy (Landau energy) neglecting the Coulomb interactions between electrons, classical Coulomb energy and the quantum energy via quantum transitions.…
Quantum Hall effect (QHE) is a macroscopic manifestation of quantized states which only occurs in confined two-dimensional electron gas (2DEG) systems. Experimentally, QHE is hosted in high mobility 2DEG with large external magnetic field…
We present a spectrum of experimental data on the fractional quantum Hall effect (FQHE) states in the first excited Landau level, obtained in an ultrahigh mobility two-dimensional electron system (2DES) and at very low temperatures and…
Quantum transport properties in quantum Hall wires in the presence of spatially correlated disordered magnetic fields are investigated numerically. It is found that the correlation drastically changes the transport properties associated…
We study the quantum localization phenomena for a random matrix model belonging to the Gaussian orthogonal ensemble (GOE). An oscillating external field is applied on the system. After the transient time evolution, energy is saturated to…
We reexamine the charge transport induced by a weak electric field in two-dimensional quantum Hall systems in a finite, periodic box at very low temperatures. The resulting linear response coefficients consist of the time-independent term…