Spin flux and magnetic solitons in an interacting two-dimensional electron gas: Topology of two-valued wave functions

Journal Article · Sun Jan 01 00:00:00 EST 1995 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.51.381· OSTI ID:6712688

John, S; Golubentsev, A ^[1]

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1. Department of Physics, University of Toronto, Toronto, Ontario, M5S 1A7 (Canada)

For a topological antiferromagnet on a square lattice, with the standard Hartree-Fock, spin-density-wave decoupling of the on-site Hubbard interaction, there is an exact mapping of the low-energy one-electron excitation spectrum to a relativistic Dirac continuum field theory. In this field theory, the Dirac mass gap is precisely the Mott-Hubbard charge gap and the continuum field variable is an eight-component Dirac spinor describing the components of physical electron-spin amplitude on each of the four sites of the elementary plaquette in the original Hubbard model. Within this continuum model we derive explicitly the existence of hedgehog Skyrmion textures as local minima of the classical magnetic energy. These magnetic solitons carry a topological winding number [mu] associated with the vortex rotation of the background magnetic moment field by a phase angle 2[pi][mu] along a path encircling the soliton. Such solitons also carry a spin flux of [mu][pi] through the plaquette on which they are centered. The [mu]=1 hedgehog Skyrmion describes a local transition from the topological (antiperiodic) sector of the one-electron Hilbert space to the nontopological sector. We derive from first principles the existence of deep level localized electronic states within the Mott-Hubbard charge gap for the [mu]=1 and 2 solitons. The spectrum of localized states is symmetric about [ital E]=0 and each subgap electronic level can be occupied by a pair of electrons in which one electron resides primarily on one sublattice and the second electron on the other sublattice. It is suggested that flux-carrying solitons and the subgap electronic structure which they induce are important in understanding the physical behavior of doped Mott insulators.

• OSTI ID: 6712688
• Journal Information: Physical Review, B: Condensed Matter; (United States), Vol. 51:1; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ELECTRON GAS
WAVE FUNCTIONS
HIGH-TC SUPERCONDUCTORS
HUBBARD MODEL
MAGNETIC FIELDS
MANY-BODY PROBLEM
SO-3 GROUPS
SOLITONS
SPINORS
TOPOLOGY
TWO-DIMENSIONAL CALCULATIONS
CRYSTAL MODELS
FLUIDS
FUNCTIONS
GASES
LIE GROUPS
MATHEMATICAL MODELS
MATHEMATICS
QUASI PARTICLES
SO GROUPS
SUPERCONDUCTORS
SYMMETRY GROUPS
665400* - Quantum Physics Aspects of Condensed Matter- (1992-)