6 research outputs found
Frustrated quantum-spin system on a triangle coupled with lattice vibrations - Correspondence to Longuet-Higgins et al.'s Jahn-Teller model -
We investigate the quantum three spin model
of spin on a triangle, in which spins are coupled with
lattice-vibrational modes through the exchange interaction depending on
distances between spin sites. The present model corresponds to the dynamic
Jahn-Teller system proposed by Longuet-Higgins {\it et al.},
Proc.R.Soc.A.{\bf 244},1(1958). This correspondence is revealed by using the
transformation to Nakamura-Bishop's bases proposed in Phys.Rev.Lett.{\bf
54},861(1985). Furthermore, we elucidate the relationship between the behavior
of a chiral order parameter and
that of the electronic orbital angular momentum in vibronic model: The regular oscillatory behavior of the expectation value
. The increase of the additional
anharmonicity(chaoticity) is found to yield a rapidly decaying irregular
oscillation of
Chaos and its quantization in dynamical Jahn-Teller systems
We investigate the Jahn-Teller system for the purpose to
reveal the nature of quantum chaos in crystals. This system simulates the
interaction between the nuclear vibrational modes and the electronic motion in
non-Kramers doublets for multiplets of transition-metal ions. Inclusion of the
anharmonic potential due to the trigonal symmetry in crystals makes the system
nonintegrable and chaotic. Besides the quantal analysis of the transition from
Poisson to Wigner level statistics with increasing the strength of
anharmonicity, we study the effect of chaos on the electronic orbital angular
momentum and explore the magnetic -factor as a function of the system's
energy. The regular oscillation of this factor changes to a rapidly-decaying
irregular oscillation by increasing the anharmonicity (chaoticity).Comment: 8 pages, 6 figure