INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, cilt.81, ss.253-259, 2001 (SCI İndekslerine Giren Dergi)
The estimations of the stability region of the lattice ferromagnetic ground state in the space of model parameters are found. For the triangular lattice strip formed by L segments with the total number of electrons N = L + 1 we derived the effective Hamiltonians describing the low-energy states of the strips and obtained the analytical estimations for above stability region. The possibility of the magnetic transition with the jump of the ground-state spin between minimal and maximal values has also been shown. For the strip with N = L and an alternating value of the one-site potential energy, we have obtained the exact relation between electron parameters, which provides the ferromagnetic character of the lattice ground state. (C) 2001 John Wiley & Sons, Inc.