Berry phase of the composite-fermion Fermi sea: Effect of Landau-level mixing

Songyang Pu, Mikael Fremling, J. K. Jain

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

We construct explicit lowest-Landau-level wave functions for the composite-fermion Fermi sea and its low-energy excitations following a recently developed approach [Pu, Wu, and Jain, Phys. Rev. B 96, 195302 (2017)2469-995010.1103/PhysRevB.96.195302] and demonstrate them to be very accurate representations of the Coulomb eigenstates. We further ask how the Berry phase associated with a closed loop around the Fermi circle, predicted to be π in a Dirac composite fermion theory satisfying particle-hole symmetry [D. T. Son, Phys. Rev. X 5, 031027 (2015)2160-330810.1103/PhysRevX.5.031027], is affected by Landau-level mixing. For this purpose, we consider a simple model wherein we determine the variational ground state as a function of Landau-level mixing within the space spanned by two basis functions: the lowest-Landau-level projected and the unprojected composite-fermion Fermi sea wave functions. We evaluate Berry phase for a path around the Fermi circle within this model following a recent prescription, and find that it rotates rapidly as a function of Landau-level mixing. We also consider the effect of a particle-hole symmetry-breaking three-body interaction on the Berry phase while confining the Hilbert space to the lowest Landau level. Our study deepens the connection between the π Berry phase and the exact particle-hole symmetry in the lowest Landau level.

Original languageEnglish (US)
Article number075304
JournalPhysical Review B
Volume98
Issue number7
DOIs
StatePublished - Aug 3 2018

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Fermions
fermions
Wave functions
composite materials
Composite materials
Excitation energy
Hilbert spaces
Ground state
wave functions
particle theory
symmetry
Hilbert space
confining
broken symmetry
eigenvectors
ground state
excitation

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

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abstract = "We construct explicit lowest-Landau-level wave functions for the composite-fermion Fermi sea and its low-energy excitations following a recently developed approach [Pu, Wu, and Jain, Phys. Rev. B 96, 195302 (2017)2469-995010.1103/PhysRevB.96.195302] and demonstrate them to be very accurate representations of the Coulomb eigenstates. We further ask how the Berry phase associated with a closed loop around the Fermi circle, predicted to be π in a Dirac composite fermion theory satisfying particle-hole symmetry [D. T. Son, Phys. Rev. X 5, 031027 (2015)2160-330810.1103/PhysRevX.5.031027], is affected by Landau-level mixing. For this purpose, we consider a simple model wherein we determine the variational ground state as a function of Landau-level mixing within the space spanned by two basis functions: the lowest-Landau-level projected and the unprojected composite-fermion Fermi sea wave functions. We evaluate Berry phase for a path around the Fermi circle within this model following a recent prescription, and find that it rotates rapidly as a function of Landau-level mixing. We also consider the effect of a particle-hole symmetry-breaking three-body interaction on the Berry phase while confining the Hilbert space to the lowest Landau level. Our study deepens the connection between the π Berry phase and the exact particle-hole symmetry in the lowest Landau level.",
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Berry phase of the composite-fermion Fermi sea : Effect of Landau-level mixing. / Pu, Songyang; Fremling, Mikael; Jain, J. K.

In: Physical Review B, Vol. 98, No. 7, 075304, 03.08.2018.

Research output: Contribution to journalArticle

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