Related papers: Evidence for Skyrmions and Single Spin Flips in th…
A novel type of charged excitation, known as a Skyrmion, has recently been discovered in quantum Hall systems with filling factor near \nu = 1. A Skyrmion -- which can be thought of as a topological twist in the spin density of the electron…
By carefully considering a family of wave functions for Skyrmions in simple quantum Hall states, whose members are labelled by a non-negative integer and which properly generalizes the traditional Laughlin quasiparticle, we argue that the…
Low lying excitations of electron liquids in the fractional quantum Hall (FQH) regime are studied by resonant inelastic light scattering methods. We present here results from charge and spin excitations of FQH states in the lowest…
It is verified that, at small Zeeman energies, the charged excitations in the vicinity of 1/3 filled Landau level are skyrmions of composite fermions, analogous to the skyrmions of electrons near filling factor unity. These are found to be…
We analyze bilayer quantum Hall ferromagnets, whose underlying symmetry group is SU(4). Spin-pseudospin coherence develops spontaneously when the total electron density is low enough. Quasiparticles are CP^3 skyrmions. One skyrmion induces…
If the Zeeman energy is small, the lowest energy excitations of a two dimensional electron gas at filling factor nu=1 are spin waves (spin flip excitations). At nu slightly larger (smaller) than unity, reversed spin electrons (spin holes)…
We analyze statistical interactions of skyrmions in the quantum Hall system near a critical filling fraction in the framework of the Ginzburg-Landau model. The phase picked up by the wave-function during an exchange of two skyrmions close…
The spin polarization versus temperature at or near a fully filled lowest Landau level is explored for finite-size systems in a periodic rectangular geometry. Our results at $\nu=1$ which also include the finite-thickness correction are in…
Inelastic light scattering spectroscopy around the \nu=1/3 filling discloses a novel type of cyclotron spin-flip excitation in a quantum Hall system in addition to the excitations previously studied. The excitation energy of the observed…
We report inelastic light scattering experiments in the fractional quantum Hall regime at filling factors $\nu\lesssim1/3$. A spin mode is observed below the Zeeman energy. The filling factor dependence of the mode energy is consistent with…
We argue that the dissipative transport in ferromagnetic quantum Hall effect liquids at $\nu=2N+1$ is dominated by the thermal activation of pairs consisting of an electron and an antiskyrmion (topological texture which represents a hole…
We investigate the 1/3 fractional quantum Hall state with one and two quasiparticle excitations. It is shown that the quasiparticle excitations are best described as excited composite fermions occupying higher composite-fermion quasi-Landau…
The tilting angular dependence of the energy gap was measured in the bilayer quantum Hall state at the Landau level filling $\nu=1$ by changing the density imbalance between the two layers. The observed gap behavior shows a continuous…
Spin splitting in the integer quantum Hall effect is investigated for a series of Al$_{x}$Ga$_{1-x}$As/GaAs heterojunctions and quantum wells. Magnetoresistance measurements are performed at mK temperature to characterize the electronic…
We study the spin of the localised quasiparticle excitations of lowest-Landau-level quantum Hall states defined on a disk. The spin that we propose satisfies the spin-statistics relation and can be used to reconstruct the topological…
The inter-Landau-level spin excitations of quantum Hall states at filling factors nu=2 and 4/3 are investigated by exact numerical diagonalization for the situation in which the cyclotron (hbar*omega_c) and Zeeman (E_Z) splittings are…
We present a microscopic theory of skyrmion and antiskyrmion excitations in fractional quantum Hall systems, and calculate in an analytical fashion their excitation energies. From the calculated net spins at various fractional filling…
Motivated by the discovery of extremely low energy collective modes in the fractional quantum Hall effect (Kang, Pinczuk {\em et al.}), with energies below the Zeeman energy, we study theoretically the spin reversed excitations for…
Recent experiments on strongly correlated bilayer quantum Hall systems strongly suggest that, contrary to the usual assumption, the electron spin degree of freedom is not completely frozen either in the quantum Hall or in the compressibles…
We report on our accurate evaluation of spin polarizations of the ground state and particle-hole gaps for partially-filled lowest Landau level, observed in recent experiments on graphene subjected to ultra-high magnetic fields. We find that…