We argue that the naively expected singularities of the Fermi surface, in the mixed composite boson-composite fermion states proposed [S.H. Simon et al., Phys. Rev. Lett. 91, 046803 (2003)] for the evolution of $\ensuremath{\nu}=1$ bilayer quantum Hall system with distance, are obliterated. Our conclusion is based on a careful analysis of the momentum distribution in $\ensuremath{\nu}=\frac{1}{2}$ single-layer composite-fermion state. We point out to a possibility of the phenomenon hitherto unknown outside Kondo lattice systems when, in a translationally invariant system, Fermi-liquid-like portion of electrons enlarges its volume.We argue that the naively expected singularities of the Fermi surface, in the mixed composite boson-composite fermion states proposed [S.H. Simon et al., Phys. Rev. Lett. 91, 046803 (2003)] for the evolution of $\ensuremath{\nu}=1$ bilayer quantum Hall system with distance, are obliterated. Our conclusion is based on a careful analysis of the momentum distribution in $\ensuremath{\nu}=\frac{1}{2}$ single-layer composite-fermion state. We point out to a possibility of the phenomenon hitherto unknown outside Kondo lattice systems when, in a translationally invariant system, Fermi-liquid-like portion of electrons enlarges its volume.

arXiv:cond-mat/0405554Physical Review BAug 1, 20042 citations

Fermions and the Fermi surface

Lecture notes in physics. M, MonographsJan 1, 19970 citations

Numerical study of anisotropy in a composite Fermi liquid

Matteo Ippoliti, Scott Geraedts, R. N. Bhatt

We perform density-matrix renormalization group studies of a two-dimensional electron gas in a high perpendicular magnetic field and with an anisotropic band mass. At half filling in the lowest Landau level, such a system is a Fermi liquid of composite fermions. By measuring the Fermi surface of these composite fermions, we determine a relationship between the anisotropy of composite fermion dispersion ${\ensuremath{\alpha}}_{CF}$ and the original anisotropy ${\ensuremath{\alpha}}_{F}$ of the fermion dispersion at zero magnetic field. For systems where the electrons interact via a Coulomb interaction, we find ${\ensuremath{\alpha}}_{CF}=\sqrt{{\ensuremath{\alpha}}_{F}}$ within our numerical accuracy. The same result has been found concurrently in recent experiments. We also find that the relationship between the anisotropies is dependent on the form of the electron-electron interaction.We perform density-matrix renormalization group studies of a two-dimensional electron gas in a high perpendicular magnetic field and with an anisotropic band mass. At half filling in the lowest Landau level, such a system is a Fermi liquid of composite fermions. By measuring the Fermi surface of these composite fermions, we determine a relationship between the anisotropy of composite fermion dispersion ${\ensuremath{\alpha}}_{CF}$ and the original anisotropy ${\ensuremath{\alpha}}_{F}$ of the fermion dispersion at zero magnetic field. For systems where the electrons interact via a Coulomb interaction, we find ${\ensuremath{\alpha}}_{CF}=\sqrt{{\ensuremath{\alpha}}_{F}}$ within our numerical accuracy. The same result has been found concurrently in recent experiments. We also find that the relationship between the anisotropies is dependent on the form of the electron-electron interaction.

arXiv:1701.07832Physical review. B./Physical review. BMay 16, 201723 citations

Interacting Composite Fermions

Chia‐Chen Chang

Jun 22, 20060 citations

Trial wave functions for a Composite Fermi liquid on a torus

Mikael Fremling, Niall Moran, Johannes K. Slingerland +1 more

We study the two-dimensional electron gas in a magnetic field at filling fraction $ν=\frac{1}{2}$ . At this filling the system is in a gapless state which can be interpreted as a Fermi liquid of composite fermions. We construct trial wave functions for the system on a torus, based on this idea, and numerically compare these to exact wave functions for small systems found by exact diagonalization. We find that the trial wave functions give an excellent description of the ground state of the system, as well as its charged excitations, in all momentum sectors. We analyze the dispersion of the composite fermions and the Berry phase associated with dragging a single fermion around the Fermi surface and comment on the implications of our results for the current debate on whether composite fermions are Dirac fermions.We study the two-dimensional electron gas in a magnetic field at filling fraction $ν=\frac{1}{2}$. At this filling the system is in a gapless state which can be interpreted as a Fermi liquid of composite fermions. We construct trial wave functions for the system on a torus, based on this idea, and numerically compare these to exact wave functions for small systems found by exact diagonalization. We find that the trial wave functions give an excellent description of the ground state of the system, as well as its charged excitations, in all momentum sectors. We analyze the dispersion of the composite fermions and the Berry phase associated with dragging a single fermion around the Fermi surface and comment on the implications of our results for the current debate on whether composite fermions are Dirac fermions.

arXiv:1711.01217Bulletin of the American Physical SocietyJan 1, 20170 citations

We study the two-dimensional electron gas in a magnetic field at filling fraction

ν=\frac{1}{2}

. At this filling the system is in a gapless state which can be interpreted as a Fermi liquid of composite fermions. We construct trial wave functions for the system on a torus, based on this idea, and numerically compare these to exact wave functions for small systems found by exact diagonalization. We find that the trial wave functions give an excellent description of the ground state of the system, as well as its charged excitations, in all momentum sectors. We analyze the dispersion of the composite fermions and the Berry phase associated with dragging a single fermion around the Fermi surface and comment on the implications of our results for the current debate on whether composite fermions are Dirac fermions.