Ground State Property of an Alternating-Spin Ladder with Additional Diagonal Interactions

Abstract

The ground state property of the alternating-spin ladder is studied in the case that the system involves an antiferromagnetic intra-chain interaction as well as two kinds of inter-chain interactions; one is between spins of the same magnitude and the other is between spins with different magnitudes. The calculation has been carried out by the exact diagonalization method. As a consequence of the competition among interactions, the system is revealed to show an interesting variety of phases in the ground state; the results are summarized as a phase diagram. A ferrimagnetic and two type of singlet ground states appear, and natures of two singlet phases are discussed.