scholarly journals The half-filled Landau level: The case for Dirac composite fermions

Science ◽  
2016 ◽  
Vol 352 (6282) ◽  
pp. 197-201 ◽  
Author(s):  
S. D. Geraedts ◽  
M. P. Zaletel ◽  
R. S. K. Mong ◽  
M. A. Metlitski ◽  
A. Vishwanath ◽  
...  
Keyword(s):  
Landau Level ◽  
Composite Fermions

scholarly journals Particle-flux separation in Chern-Simons theory and the Landau-level gap of composite fermions

1995 ◽  
Vol 52 (14) ◽  
pp. 10547-10560 ◽  
Author(s):  
Ikuo Ichinose ◽  
Tetsuo Matsui ◽  
Masaru Onoda
Keyword(s):  
Landau Level ◽  
Particle Flux ◽  
Simons Theory ◽  
Composite Fermions ◽  
Chern Simons ◽  
Chern Simons Theory

scholarly journals COMPOSITE FERMIONS CLOSE TO THE ONE-HALF FILLING OF THE LOWEST LANDAU LEVEL REVISITED

2005 ◽  
Vol 19 (04) ◽  
pp. 775-782
Author(s):  
BEHNAM FARID
Keyword(s):  
Landau Level ◽  
Microscopic Theory ◽  
Mean Free Path ◽  
Experimental Results ◽  
Two Dimensional ◽  
Composite Fermions ◽  
Lowest Landau Level ◽  
Longitudinal Conductivity ◽  
Half Filling ◽  
The One

By strictly adhering to the microscopic theory of composite fermions (CFs) for the Landau-level filling fractions ν e =p/(2p+1), we reproduce, with remarkable accuracy, the surface-acoustic-wave (SAW)-based experimental results by Willett and co-workers concerning two-dimensional electron systems with ν e close to ½. Our results imply that the electron band mass m b , as distinct from the CF mass m⋆, must undergo a substantial increase under the conditions corresponding to ν e ≈ ½. In view of the relatively low aerial electronic densities n e to which the underlying SAW experiments correspond, our finding conforms with the experimental results by Shashkin et al. [Phys. Rev. B 66, 073303 (2002)], concerning two-dimensional electrons in silicon, that signal sharp increase in m b for n e decreasing below approximately 2×1011 cm -2. We further establish that a finite mean-free path ℓ0 is essential for the observed linearity of the longitudinal conductivity σxx(q) as deduced from the SAW velocity shifts.

scholarly journals Spectral Function Analysis of Fermi Liquids and of Composite Fermions in A Finite Magnetic Field: Renormalised Gaps

1997 ◽  
Vol 11 (12) ◽  
pp. 1477-1502 ◽  
Author(s):  
S. Curnoe ◽  
P. C. E. Stamp
Keyword(s):  
Landau Level ◽  
Function Analysis ◽  
Level Structure ◽  
Quantum Hall ◽  
Composite Fermions ◽  
Filling Fraction ◽  
Fractional Quantum ◽  
Fractional Quantum Hall ◽  
Self Energy ◽  
Level Quantization

We consider the self-energy and quasiparticle spectrum, for both electrons interacting with phonons, and composite fermions interacting with gauge fluctuations. In both cases we incorporate the singular structure arising from Landau level quantization in a finite field. This is then used to determine the renormalised gap between the Fermi energy and the first excited states. The electron–phonon problem is treated for both Debye and Einstein phonons. In the case of composite fermions, it is found that the singular Landau level structure strongly affects the renormalised gap in the intermediate coupling regime, which is relevant to experiments on the fractional quantum Hall effect. We compare our findings with measurements of the gap in fractional Hall states with filling fraction ν near ν=1/2.

scholarly journals ON THE RESPONSE OF COMPOSITE FERMIONS TO WEAK ELECTROSTATIC POTENTIALS

2004 ◽  
Vol 18 (22) ◽  
pp. 3047-3055 ◽  
Author(s):  
BEHNAM FARID
Keyword(s):  
Magnetic Field ◽  
Landau Level ◽  
Electrostatic Potentials ◽  
Two Dimensional ◽  
Composite Fermions ◽  
Electron Systems ◽  
Dimensional Electron ◽  
Interacting Particles ◽  
Physical Origin ◽  
Theoretical Finding

We establish that the response to static perturbations of two-dimensional electron systems (2DESs), exposed to magnetic field B, in states with the Landau-level filling fractions ν e close to one such as 1/2, is singularly different from that of 2DESs at small ‖B‖. Thus in addition to demonstrating the severe inadequacy of the treatment of composite fermions as non-interacting particles, we show, in contradiction to a recent theoretical finding, that the physical origin of the observed behavior of the dc longitudinal magneto-resistivity for ν e ≈1/2 in periodically modulated 2DESs remains to be determined.

scholarly journals Quasiparticle Behavior of Composite Fermions in the Half-Filled Landau Level

1997 ◽  
Vol 78 (2) ◽  
pp. 314-317 ◽  
Author(s):  
Peter Kopietz ◽  
Guillermo E. Castilla
Keyword(s):  
Landau Level ◽  
Composite Fermions

scholarly journals Search for composite fermions at filling factor 5/2: Role of Landau level and subband index

2017 ◽  
Vol 95 (16) ◽  
Author(s):  
M. A. Mueed ◽  
D. Kamburov ◽  
Md. Shafayat Hossain ◽  
L. N. Pfeiffer ◽  
K. W. West ◽  
...  
Keyword(s):  
Landau Level ◽  
Filling Factor ◽  
Composite Fermions

scholarly journals Composite Fermions in the Hilbert Space of the Lowest Electronic Landau Level

1997 ◽  
Vol 11 (22) ◽  
pp. 2621-2660 ◽  
Author(s):  
J. K. Jain ◽  
R. K. Kamilla
Keyword(s):  
Landau Level ◽  
Ground State ◽  
Quantum Hall ◽  
Monte Carlo Study ◽  
Composite Fermions ◽  
Composite Fermion ◽  
Fractional Quantum ◽  
Fractional Quantum Hall ◽  
Lowest Landau Level ◽  
Standard Manner

Single particle basis functions for composite fermions are obtained from which many-composite fermion states confined to the lowest electronic Landau level can be constructed in the standard manner, i.e. by building Slater determinants. This representation enables a Monte Carlo study of systems containing a large number of composite fermions, yielding new quantitative and qualitative information. The ground state energy and the gaps to charged and neutral excitations are computed for a number of fractional quantum Hall effect (FQHE) states, earlier off-limits to a quantitative investigation. The ground state energies are estimated to be accurate to ~0.1% and the gaps at the level of a few percent. It is also shown that at Landau level fillings smaller than or equal to 1/9 the FQHE is unstable to a spontaneous creation of excitons of composite fermions. In addition, this approach provides new conceptual insight into the structure of the composite fermion wave functions, resolving in the affirmative the question of whether it is possible to motivate the composite fermion theory entirely within the lowest Landau level, without appealing to higher Landau levels.

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