Related papers: Quantum Hall to Insulator Transition in the Bilaye…
The bilayer quantum Hall system at a total filling of $\nu_T=1$ has long resisted explanation in terms of a true counterflow superfluid, though many experimental features can be seen to be "almost" that of a superfluid. It is widely…
We consider the zero-filled quantum-Hall ferromagnetic state of bilayer graphene subject to a kink-like perpendicular electric field, which generates domain walls in the electronic state and low-energy collective modes confined to move…
We measured the magnetoresistance of bilayer quantum Hall (QH) effects at the fractional filling factor $\nu =2/3$ by changing the total electron density and the density difference between two layers. Three different QH states were…
Bosonic Integer Quantum Hall (IQH) phases are a class of symmetry protected topological (SPT) phases that, similar to the fermionic IQH states, support a quantized Hall conductance. They, however, require interactions for their realization.…
Using a combination of heat pulse and nuclear magnetic resonance techniques we demonstrate that the phase boundary separating the interlayer phase coherent quantum Hall effect at $\nu_T = 1$ in bilayer electron gases from the weakly coupled…
We revisit the physics of electron gas bilayers in the quantum Hall regime [Nature, 432 (2004) 691; Science, 305 (2004) 950], where transport and tunneling measurements provided evidence of a superfluid phase being present in the system.…
We develop a theory of a direct, continuous quantum phase transition between a bosonic Laughlin fractional quantum Hall (FQH) state and a superfluid, generalizing the Mott insulator to superfluid phase diagram of bosons to allow for the…
For sufficiently strong in-plane magnetic field a $\nu_T=1$ bilayer quantum Hall pseudo-ferromagnet is expected to exhibit a soliton lattice. For sufficiently close layers and large in-plane field, we predict this incommensurate ``planar''…
We present an effective Hamiltonian for a bilayer quantum Hall system at filling factor $\nu=1$ neglecting charge fluctuations. Our model is formulated in terms of spin and pseudospin operators and is an exact representation of the system…
The mapping between the metal-insulator transition of the quantum Hall system and a superfluid-to-insulator transition is revisited based on a disordered anyon model. The one-parameter scaling of the superfluid-to-insulator transition is…
A bilayer system of two-dimensional electron gases in a perpendicular magnetic field exhibits rich phenomena. At total filling factor $\nu_{tot} = 1$, as one increases the layer separation, the bilayer system goes from an interlayer…
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,…
Double layer quantum Hall systems have interesting properties associated with interlayer correlations. At $\nu =1/m$ where $m$ is an odd integer they exhibit spontaneous symmetry breaking equivalent to that of spin $1/2$ easy-plane…
We extend the Composite Boson theory to study slightly im-balanced bi-layer Quantum Hall systems. In the global $ U(1) $ symmetry breaking excitonic superfluid side, as the imbalance increases, the system supports continuously changing…
We present a microscopic study of the interlayer spacing d versus in-plane magnetic field $B_\parallel$ phase diagram for bilayer quantum Hall (QH) pseudo-ferromagnets. In addition to the interlayer charge balanced commensurate and…
The superfluid to Mott insulator transition and the superradiant transition are textbook examples for quantum phase transition and coherent quantum optics, respectively. Recent experiments in ETH and Hamburg succeeded in loading degenerate…
We investigate a transition between a two-dimensional topological insulator conduction state, characterized by a conductance $G=2$ (in fundamental units $e^2/h$) and a Chern insulator with $G=1$, induced by polarized magnetic impurities.…
Bilayer quantum Hall systems have a broken symmetry ground state at filling factor $\nu=1$ which can be viewed either as an excitonic superfluid or as a pseudospin ferromagnet. We present a theory of inter-layer transport in quantum Hall…
We show that in a commensurate bosonic ladder, a quantum phase transition occurs between a Mott insulator and a superfluid when interchain hopping increases. We analyse the properties of such a transition as well as the physical properties…
We study the phase diagram of quantum Hall bilayer systems with total filing $\nu_T=1/2+1/2$ of the lowest Landau level as a function of layer distances $d$. Based on numerical exact diagonalization calculations, we obtain three distinct…