Prog. Theor. Phys. Supplement No.145 (2002) pp. 320-325
Magnetic Properties of S=1/2 Heisenberg Chains with Bond Alternation and Randomness on the Strong Bonds
Department of Physics, Saitama University, Saitama 338-8570, Japan
(Received December 27, 2001)
The S=1/2 Heisenberg chains with bond alternation and randomness on the
strong bonds are studied by the density matrix renormalization group method.
It is assumed that the odd-th bond is antiferromagnetic with strength J
and the even-th bond can take the values J A and J F
(J A > J > 0 > J F)
randomly. The ground state of this model interpolates between the Haldane
and dimer phases via a randomness dominated intermediate phase. On the
basis of the scaling of the low energy spectrum and mean field
treatment of the interchain coupling, we find that the magnetic long
range order is induced by randomness in the intermediate regime. In
the magnetization curves, there appears a plateau at the fractional
value of the saturated magnetization. The fine structures of the
magnetization curves and low energy spectrum are understood using
the cluster picture. The relation to the recent experiment for
(CH3)2CHNH3Cu(ClxBr1-x)3 is discussed.
DOI : 10.1143/PTPS.145.320
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Citing Article(s) :
Journal of the Physical Society of Japan 72 (2003) pp. 688-693
Random Magnetism in S=1/2 Heisenberg Chains with Bond Alternation and Randomness on the Strong Bonds
Journal of the Physical Society of Japan 72 (2003) pp. 789-792
Antiferromagnetic Order in an Ferromagnetic–Antiferromagnetic Random Alternating Quantum Spin Chain: (CH3)2CHNH3Cu(Clx Br1-x)3
Journal of the Physical Society of Japan 72 (2003) pp. 911-915
Magnetization Plateaux in Random Frustrated S=1/2 Heisenberg Chains