相关论文: Exchange Instabilities in Semiconductor Double Qua…
We investigate theoretically the effects of intralayer and interlayer exchange in biased double-layer electron and hole systems, in the absence of a magnetic field. We use a variational Hartree-Fock-like approximation to analyze the effects…
We prove that the predicted charge transfer state in symmetric bilayers of two dimensional electron gases is always unstable at zero bias voltage, due to interlayer correlation and/or tunneling. This is most easily seen by resorting to a…
We study the magnetic phases of two coupled two-dimensional electron gases in order to determine under what circumstances these phases may occur in real semiconductor quantum wells and what the experimental properties of the broken-symmetry…
We examine the robustness of a recently predicted exchange-induced zero-field magnetic phase in semiconductor double quantum wells in which each well is spin-polarized and the polarization vectors are antiparallel. Magnetic instabilities…
We use self-consistent quantum transport theory to investigate the influence of electron-electron interactions on interlayer transport in semiconductor electron bilayers in the absence of an external magnetic field. We conclude that, even…
At strong magnetic fields double-layer two-dimensional-electron-gas systems can form an unusual broken symmetry state with spontaneous inter-layer phase coherence. The system can be mapped to an equivalent system of pseudospin $1/2$…
In a bilayer electronic system the layer index may be viewed as the z-component of an isospin-1/2. An XY isospin-ordered ferromagnetic phase was observed in quantum Hall systems and is predicted to exist at zero magnetic field at low…
We study intersubband spin density collective modes in double-layer quantum Hall systems at $\nu=2$ within the time-dependent Hartree-Fock approximation. We find that these intersubband spin density excitations may soften under…
We theoretically consider bilayers of two dimensional (2D) electron gases as in semiconductor quantum wells, and investigate possible spontaneous symmetry breaking transitions at low carrier densities driven by interlayer Coulomb…
Due to the competition between spatial and magnetic confinement, the density of states of a quasi two-dimensional system deviates from the ideal step-like form both quantitatively and qualitatively. We study how this affects the…
We review recent transport experiments that reveal two-threshold voltage-current characteristics, marked by a significant increase in noise between the two threshold voltages, at low electron densities in the insulating regime in…
We study the influence of quantizing perpendicular magnetic fields on the ground state of a bilayer with electron and hole fluids separated by an opaque tunnel barrier. In the absence of a field, the ground state at low carrier densities is…
We find that the behaviors of the voltage-current characteristics as one enters the low-density insulating state and integer quantum Hall insulating states in the ultra-clean two-dimensional electron system in SiGe/Si/SiGe quantum wells are…
The local density of states of a degenerate semiconductor is investigated at low magnetic fields. In order to realize this experiment, we designed a strongly asymmetric double-barrier heterostructure with heavily doped contacts and study…
We study the effects of disorder on the interlayer transport properties of disordered semiconductor bilayers outside of the quantum Hall regime by performing self-consistent quantum transport calculations. We find that the addition of…
Equilibrium properties of electrons in double-heterojunction AlGaAs/GaAs\AlGaAs structures are investigated theoretically, using a full self-consistent numerical method. The transition from single to bilayer electron systems is discussed…
Spatially indirect electron-hole exciton condensates stabilized by interlayer Fock exchange interactions have been predicted in systems containing a pair of two-dimensional semiconductor or semimetal layers separated by a thin tunnel…
We use interlayer tunneling to study bilayer 2D electron systems at $\nu_T = 1$ over a wide range of charge density imbalance, $\Delta \nu =\nu_1-\nu_2$, between the two layers. We find that the strongly enhanced tunneling associated with…
The incommensurate phase of a bilayer quantum Hall state is found to have a ``rippled'' dipole charge density whenever the layers are unbalanced. This tunable dipole-density-wave instability could be detected by sensitive capacitance…
Tunneling and Coulomb drag are sensitive probes of spontaneous interlayer phase coherence in bilayer two-dimensional electron systems at total Landau level filling factor $\nu_T = 1$. We find that the phase boundary between the interlayer…