Quantum disordered phase on the frustrated honeycomb lattice

In the present paper we study the phase diagram of the Heisenberg model on the honeycomb lattice with antiferromagnetic interactions up to third neighbors along the line J₂=J₃ that includes the point J₂=J₃=J₁/2, corresponding to the highly frustrated point where the classical ground state has macros...

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Detalles Bibliográficos
Autores: Cabra, Daniel Carlos, Lamas, Carlos Alberto, Rosales, Héctor Diego
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2011
País:Argentina
Institución:Universidad Nacional de La Plata
Repositorio:SEDICI (UNLP)
Idioma:inglés
OAI Identifier:oai:sedici.unlp.edu.ar:10915/126230
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/126230
Access Level:acceso abierto
Palabra clave:Física
Physics
Lattice (order)
Antiferromagnetism
Quantum limit
Heisenberg model
Mean field theory
Condensed matter physics
Quantum mechanics
Ground state
Boson
Phase diagram
Descripción
Sumario:In the present paper we study the phase diagram of the Heisenberg model on the honeycomb lattice with antiferromagnetic interactions up to third neighbors along the line J₂=J₃ that includes the point J₂=J₃=J₁/2, corresponding to the highly frustrated point where the classical ground state has macroscopic degeneracy. Using the linear spin-wave theory and the Schwinger boson technique followed by a mean field decoupling and exact diagonalization for small systems, we find an intermediate phase with a spin gap and short-range Néel correlations in the strong quantum limit S=½. All techniques provide consistent results which allow us to predict the existence of a quantum disordered phase, which may have been observed in recent high-field ESR measurements in manganites.