Related papers: Density-controlled quantum Hall ferromagnetic tran…
We report on transport experiments through high-mobility gate-tunable undoped InSb QWs. Due to the elimination of any Si modulation doping, the gate-defined two-dimensional electron gases in the quantum wells display a significantly…
We report a new manifestation of first-order magnetic transitions in two-dimensional electron systems. This phenomenon occurs in aluminum arsenide quantum wells with sufficiently low carrier densities and appears as a set of hysteretic…
We study a two-dimensional electron system where the electrons occupy two conduction band valleys with anisotropic Fermi contours and strain-tunable occupation. We observe persistent quantum Hall states at filling factors $\nu = 1/3$ and…
Spin relaxation in a quantum Hall ferromagnet, where filling is $\nu=1, 1/3, 1/5,...$, can be considered in terms of spin wave annihilation/creation processes. Hyperfine coupling with the nuclei of the GaAs matrix provides spin…
The competition between the Zeeman energy and the Rashba and Dresselhaus spin-orbit couplings is studied for fractional quantum Hall states by including correlation effects. A transition of the direction of the spin-polarization is…
In this paper we propose that, quantized and nearly half-quantized intrinsic anomalous Hall effect can be induced by in-plane external magnetic field through the Zeeman coupling in non-magnetic 2D systems with sizeable spin-orbital coupling…
It is known experimentally that at not very large filling factors $\nu$ the quantum Hall conductivity peaks corresponding to the same Landau level number $N$ and two different spin orientations are well separated. These peaks occur at…
In a graphene Landau level (LL), strong Coulomb interactions and the fourfold spin/valley degeneracy lead to an approximate SU(4) isospin symmetry. At partial filling, exchange interactions can spontaneously break this symmetry, manifesting…
We have studied quantum-well-confined holes based on the Luttinger-model description for the valence band of typical semiconductor materials. Even when only the lowest quasi-two-dimensional (quasi-2D) subband is populated, the static spin…
We have developed an ensemble density functional theory which includes spin degrees of freedom for nonuniform quantum Hall systems. We have applied this theory using a local-spin-density approximation to study the edge reconstruction of…
We present the phase diagram of a ferromagnetic quantum Hall effect liquid in a narrow quantum well with vanishing single-particle Zeeman splitting, $\epsilon_{{\rm Z}}$ and pronounced spin-orbit coupling. Upon decreasing $\epsilon_{{\rm…
The spectroscopic properties of a spin polarized two-dimensional hole gas are studied in modulation doped (Cd,Mn)Te quantum wells. The giant Zeeman effect induces a significant spin splitting even at very small values of the applied field.…
We study the magnetotransport properties of dual-gated graphene bilayers, in which the total density and layer density imbalance are independently controlled. As the bilayer is imbalanced we observe the emergence of a quantum Hall state…
The quantum anomalous Hall effect is a intriguing topological nontrivial phase arising from spontaneous magnetization and spin-orbit coupling. However, the tremendously harsh realizing requirements of the quantum anomalous Hall effects in…
We examine the magnetic field driven insulator-quantum Hall-insulator transitions of the two dimensional hole gas in a Ge/SiGe quantum well. We observe direct transitions between low and high magnetic field insulators and the $\nu=1$…
We report on an observation of a fractional quantum Hall effect in an ultra-high quality two-dimensional hole gas hosted in a strained Ge quantum well. The Hall resistance reveals precisely quantized plateaus and vanishing longitudinal…
Higher-order topological superconductors and superfluids host lower-dimensional Majorana corner and hinge states since novel topology exhibitions on boundaries. While such topological nontrivial phases have been explored extensively, more…
We derive an effective field-theoretical model for the one-dimensional collective mode associated with a domain wall in a quantum Hall ferromagnetic state, as realized in confined graphene systems at zero filling. To this end, we consider…
We consider the charged excitations in the quantum Hall effect with a large Zeeman splitting at filling factor nu=2. When the Zeeman splitting is increased over a critical value the groundstate undergoes a first order phase transition from…
We study a single species of fermionic atoms in an "effective" magnetic field at total filling factor $\nu_{f}=1$, interacting through a p-wave Feshbach resonance, and show that the system undergoes a quantum phase transition from a…