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Volume 6 Research & Reviews: Journal of Material Sciences
ISSN: 2321-6212 Magnetic Materials 2018
October 22-23, 2018
October 22-23, 2018 | Rome, Italy
3rd International Conference on
Magnetism and Magnetic Materials
Local gauge invariance and spin superconductivity in materials magnetic described by the two-
dimensional compass model with Heisenberg interactions
Leonardo S Lima
Centro Federal de Educação Tecnológica de Minas Gerais, Brazil
The local spontaneous symmetry breaking is a general phenomenon in condensed matter physics. It is characterized by
the fact that the action has a local symmetry but the quantum theory, instead of having a unique vacuum state which
respects this symmetry, has a family of degenerate vacua that transform into each other under the action of the symmetry
group. A simple example is given by a ferromagnetic model in which the act governing its microscopic dynamics is invariant
under spatial rotations. A kind of local gauge invariance or spontaneous breaking of U(1) gauge symmetry is realized in nature
in the phenomenon of superconductivity. We have proposed a Meissner mechanism for the spin transport in quantum spin
systems that to have various applications in spintronics. Besides, we study about the behavior of the AC spin conductivity in
the neighborhood of a quantum phase transition in a frustrated spin model such as the antiferromagnet in the compass lattice
with single ion anisotropy at T=0. Our results show the curve of conductivity varying strongly with the behavior of the critical
anisotropy Dc and J2. Katukuri et al. have shown that individual layers of Ba 2IrO4 provided a good realization of the quantum
compass model on the square lattice. Zhang et al. have used the Heisenberg model with compass interactions to study the
compound Sr2IrO4 and pointed out that it has a close resemblance to the cuprate superconductors such as La2CuO4 and that
many interesting phenomena common to the cuprates are also found in Sr2IrO4.
Res. Rev. J Mat. Sci. 2018, Volume 6
DOI: 10.4172/2321-6212-C6-030