Abstract
In this research work, frustrations arising from the geometries of triangular lattices have been studied with the aid of Ising and Heisenberg models. The study reveals that geometrical frustrations can generate multiple degeneracies in the ground state. The quantum spin flip terms in the Heisenberg model are observed to play a vital role in the partial lifting up of these degeneracies. Hence, multiple degeneracies as consequence of frustrations are more pronounced for the Ising systems, which are devoid of quantum fluctuations. The observed six- and four-fold ground state degeneracies at zero field for three spins Ising and Heisenberg systems respectively are broken down to half at finite longitudinal fields. For this three-spin system, quantum phase transitions (QPT) are observed at critical longitudinal fields of J and 1.5J respectively for the Ising and Heisenberg models. At these critical fields, the ground states are observed to shift from quasi-antiferromagnet to ferromagnet. However, for the Heisenberg three-spin system in the presence of a transverse field, no transition is observed.
Publisher
African - British Journals
Subject
Materials Chemistry,Physical and Theoretical Chemistry,Condensed Matter Physics,Electronic, Optical and Magnetic Materials,Materials Chemistry,Physical and Theoretical Chemistry,Condensed Matter Physics,Electronic, Optical and Magnetic Materials,Geochemistry and Petrology,General Materials Science,Physical and Theoretical Chemistry,Condensed Matter Physics,General Materials Science,Geochemistry and Petrology,Geophysics,General Earth and Planetary Sciences,General Earth and Planetary Sciences,General Earth and Planetary Sciences,General Earth and Planetary Sciences,General Medicine
Reference44 articles.
1. Aharoni, Amikam (2000). Introduction to the theory of ferromagnetism (2nd Ed.).Oxford: Oxford University Press. ISBN 9780198508090
2. Aminov, T.G., Shabunina, G.G. and Novotortsev, V.M.. (2014): Spin glasses in CdCr2S4- ZnCr2S4 solid solutions Russ. J. Inorg. Chem. Vol.59, pp647-657.
3. Anderson, P. W. (1973): Resonating valence bonds: A new kind of insulator?. Mater. Res. Bull. 8 (2): 153–160.
4. Anderson P.W. (1987). The resonating valence bond state in La2CuO4 and superconductivity. Science, 235, pp1196-1198.
5. Anderson, P. W. (1990). Spin Glass VII: Spin Glass as Paradigm. Physics Today. 43(3):9