Long-range interactions in antiferromagnetic quantum spin chains

We study the role of long-range dipolar interactions on antiferromagnetic spin chains, from the classical S → ∞ limit to the deep quantum case S = 1/2 , including a transverse magnetic field. To this end, we combine different techniques such as classical energy minima, classical Monte Carlo, linear...

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Autores principales: Bravo, Bárbara, Cabra, Daniel Carlos, Gómez Albarracín, Flavia Alejandra, Rossini, Gerardo Luis
Formato: Articulo Preprint
Lenguaje:Inglés
Publicado: 2017
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Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/99301
https://ri.conicet.gov.ar/11336/63636
https://journals.aps.org/prb/abstract/10.1103/PhysRevB.96.054441
https://arxiv.org/abs/1704.03420
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Sumario:We study the role of long-range dipolar interactions on antiferromagnetic spin chains, from the classical S → ∞ limit to the deep quantum case S = 1/2 , including a transverse magnetic field. To this end, we combine different techniques such as classical energy minima, classical Monte Carlo, linear spin waves, bosonization, and density matrix renormalization group (DMRG). We find a phase transition from the already reported dipolar ferromagnetic region to an antiferromagnetic region for high enough antiferromagnetic exchange. Thermal and quantum fluctuations destabilize the classical order before reaching magnetic saturation in both phases, and also close to zero field in the antiferromagnetic phase. In the extreme quantum limit S = 1/2 , extensive DMRG computations show that the main phases remain present with transition lines to saturation significatively shifted to lower fields, in agreement with the bosonization analysis. The overall picture maintains a close analogy with the phase diagram of the anisotropic XXZ spin chain in a transverse field.