相关论文: SU(3) and SU(4) singlet quantum Hall states at $\n…
Theoretical studies of the fractional quantum Hall effect (FQHE) in graphene have so far focused on the plausibility and stability of the previously known FQHE states for the interaction matrix elements appropriate for graphene. We consider…
In condensed matter physics, the study of electronic states with SU(N) symmetry has attracted considerable and growing attention in recent years, as systems with such a symmetry can often have a spontaneous symmetry-breaking effect giving…
Due to its fourfold spin-valley degeneracy, graphene in a strong magnetic field may be viewed as a four-component quantum Hall system. We investigate the consequences of this particular structure on a possible, yet unobserved, fractional…
Magnetic fields quench the kinetic energy of two dimensional electrons, confining them to highly degenerate Landau levels. In the absence of disorder, the ground state at partial Landau level filling is determined only by Coulomb…
We study many-body ground states for the partial integer fillings of the $N=1$ Landau level in graphene, by constructing a model that accounts for the lattice scale corrections to the Coulomb interactions. Interestingly, in contrast to the…
We study spin and valley ordering in the quantum Hall fractions in monolayer graphene at Landau level filling factors $\nu_G=-2+n/3$ $(n=2,4,5)$. We use exact diagonalizations on the spherical as well as toroidal geometry by taking into…
We construct a variational description for incompressible ground states and charge gaps in the N = 0 LL of graphene which accounts for the 4-fold Landau level degeneracy and for the short range interactions that break the SU(4) spin-valley…
A system at filling factor 2/3 could be a candidate for a quantum Hall ferromagnet at integer filling factor of composite fermions. Using exact diagonalization with electrons on a torus we study the transition from the singlet ground state…
Inspired by the four-fold spin-valley symmetry of relativistic electrons in graphene, we investigate a possible SU(4) fractional quantum Hall effect, which may also arise in bilayer semiconductor quantum Hall systems with small Zeeman gap.…
We have focussed to study the even-denominator fractional quantum Hall (EDFQH) states observed in monolayer graphene. In this letter, we have studied polarization mainly for the two EDFQH states at filling fractions $\nu = 1/2, 1/4$, which…
Graphene SU(4) quantum Hall symmetry is extended to SO(8), permitting analytical solutions for graphene in a magnetic field that break SU(4) spontaneously. We recover standard graphene SU(4) physics as one limit, but find new phases and new…
We investigate integer and half-integer filling states (uniform and unidimensional stripe states respectively) for graphene using the Hartree-Fock approximation. For fixed filling factor, the ratio between the scales of the Coulomb…
The double layer $\nu=2/3$ fractional quantum Hall system is studied using the edge state formalism and finite-size diagonalization subject to periodic boundary conditions. Transitions between three different ground states are observed as…
Because of the spin and Dirac-valley degrees of freedom, graphene allows the observation of one-, two- or four-component fractional quantum Hall effect in different parameter regions. We argue that some, though not all, apparently puzzling…
We study generalized spin waves in graphene under a strong magnetic field when the Landau-level filling factor is $\nu=\pm 1$. In this case, the ground state is a particular SU(4) quantum Hall ferromagnet, in which not only the physical…
In this work, we investigate the nature of the fractional quantum Hall state in the 1/3-filled second Landau level (SLL) at filling factor $\nu=7/3$ (and 8/3 in the presence of the particle-hole symmetry) via exact diagonalization in both…
Graphene and its multilayers have attracted considerable interest owing to the fourfold spin and valley degeneracy of their charge carriers, which enables the formation of a rich variety of broken-symmetry states and raises the prospect of…
Recent experiments involving tilted graphene samples have shown evidence of a continuous phase transition in the $\nu=0$ quantum Hall bulk state. We present here a simple model that supports such a transition. In addition to a long range…
We investigate the ground-state structure of the bilayer quantum Hall system at the filling factor $\nu =2$. Making an exact analysis of the ground state in the SU(4)-invariant limit, we include all other interactions as small perturbation.…
The quantum Hall effect near the charge neutrality point in bilayer graphene is investigated in high magnetic fields of up to 35 T using electronic transport measurements. In the high field regime, the eight-fold degeneracy in the zero…