Variational description of a quasihole excitation in a quantum antiferromagnet

Journal Article · Sun Mar 01 04:00:00 EST 1992 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.45.4877· OSTI ID:5000579

Boninsegni, M; Manousakis, E ^[1]

---

1. Department of Physics, Center for Materials Research and Technology Supercomputer Computations Research Institute, Florida State University, Tallahassee, Florida 32306 (United States)

An accurate variational ansatz is proposed for a single quasihole excitation in a two-dimensional quantum antiferromagnet. The trial state includes spin-hole and spin-hole-spin correlations, in addition to background antiferromagnetic spin-spin correlations. Background spin-spin correlations are induced by the Heisenberg antiferromagnetic exchange interaction and describe the zero-point motion of spin waves around the Neel state. Spin-hole and spin-hole correlations describe strings'' of spins displaced by one lattice site along the hole path. This is a generalization of the Brinkman-Rice approach to include quantum spin fluctuations. We have used the Monte Carlo method to compute the variational energy and the spectral weight of the quasihole state in the {ital t}-{ital J} model on the square lattice, with the proposed ansatz. Comparison with exact results for the 4{times}4 lattice shows very good agreement for both energy and spectral weight, at {bold k}=({pi}/2,{pi}/2) in the range 0{le}{ital t}/{ital J}{le}5. We report results for lattices of several sizes up to 16{times}16 in the above range of {ital t}/{ital J} and for the two values of {bold k} where the hole energy band attains its minimum ({bold k}=({pi}/2,{pi}/2)) and maximum ({bold k}=(0,0)).

• DOE Contract Number: FC05-85ER25000
• OSTI ID: 5000579
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 45:9; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360207* -- Ceramics
Cermets
& Refractories-- Superconducting Properties-- (1992-)
ANGULAR MOMENTUM
ANTIFERROMAGNETISM
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CORRELATIONS
CRYSTAL MODELS
HEISENBERG MODEL
HIGH-TC SUPERCONDUCTORS
HOLES
MAGNETISM
MATHEMATICAL MODELS
MONTE CARLO METHOD
NEEL TEMPERATURE
OXIDES
OXYGEN COMPOUNDS
PARTICLE PROPERTIES
PHYSICAL PROPERTIES
SPIN
SPIN WAVES
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
VARIATIONAL METHODS