arXiv subjects

Janusz Jacak

Publications and source records attributed to Janusz Jacak.

5 recordsLinked to original sources

arXiv2015

Hierarchy of fillings for FQHE in monolayer and in bilayer graphene: Explanation of $ν=-\frac{1}{2}$ fractional quantum Hall state in bilayer graphene

The commensurability condition is applied to determine the hierarchy of fractional fillings of Landau levels in monolayer and bilayer graphene. The filling rates for FQHE in graphene are found and illustrated in the first three Landau levels. The good agreement with the experimental data is achieved. The presence of even denominator filling fractions in the hierarchy for FQHE in bilayer graphene is explained.

physics.gen-ph↗

arXiv2014

Explanation of fractional hierarchy observed experimentally in higher Landau levels

The puzzle of an odd structure of fractional fillings for FQHE in higher Landau levels not repeating the hierarchy from the lowest Landau level is solved. The fractional filling rates for correlated states in higher Landau levels including spin subbands are systematically derived for the first time. Using topology-type commensurability arguments the hierarchy in higher Landau level fillings is determined in perfect agreement with the experimental observations. The relative paucity of fractional structure in higher Landau levels is explained and the criterion for pairing in states at half fillings and for other even-denominator rates of consecutive Landau levels is formulated.

physics.gen-ph↗

arXiv2014

Explanation of the odd structure of fractional Hall states in higher Landau levels and filling ratios with even denominators

The structure of fractional fillings of higher Landau levels including spin subbands is systematically derived for the first time. Using topology-type commensurability arguments for 2D charged system in the presence of strong quantizing magnetic field, a hierarchy of fillings in the higher Landau levels for FQHE and for other correlated states is determined in perfect agreement with the experimental observations. The relative paucity of fractional structure in the higher Landau levels in contrast to the plethora of filling factors for FQHE in the zeroth Landau level is explained. The filling fractions with even denominators in consecutive LLs were also identified together with the criterion for particle pairing.

physics.gen-ph↗

arXiv2012

Confirmation in graphene of wave packet multilooped dynamics related to fractional quantum Hall state

Cyclotron braid subgroups are defined in order to identify the topological origin of Laughlin correlations in 2D Hall systems. Flux-tubes and vortices for composite fermion constructions are explained in terms of unavoidably multilooped cyclotron braids. A link of braid picture with quasiclassical quantum dynamics is conjectured in order to support the phenomenological model of composite fermions with auxiliary fluxtubes, for Landau level fillings out of 1/p, p odd. The even denominator fractional lowest Landau level fillings, including Hall metal at n = 1/2, are also discussed in cyclotron braid terms. The topological arguments are utilized to explain novel experimentally observed features of the fractional quantum Hall state in graphene including the triggering role of carriers mobility for this collective state.

cond-mat.mes-hall↗

arXiv2012

The triggering role of carrier mobility in the fractional quantum Hall effect-evidence in graphene

Recent experiments on suspended graphene layers have indicated the crucial role of carrier mobility in the competition between Laughlin collective state and insulating state, probably of Wigner-crystal-type. Moreover, the fractional quantum Hall effect (FQHE) in graphene has been observed at a low carrier density where the interaction is reduced as a result of particles dilution. This suggests that the interaction may not be as important in the triggering of FQHE as expected based on the standard formulation of the composite fermions model. Here, the topological arguments are presented to explain these novel features of the FQHE in graphene and, the triggering role of carriers mobility in particular.

cond-mat.mes-hall↗