TY - JOUR

T1 - Ferrimagnetic mixed-spin ladders in weak- and strong-coupling limits

AU - Aristov, D. N.

AU - Kiselev, M. N.

PY - 2004/12/1

Y1 - 2004/12/1

N2 - We study two similar spin ladder systems with the ferromagnetic leg coupling. The first model includes two sorts of spins s=1/2 and 1, and the second model comprises only s=1/2 legs coupled by a "triangular" rung exchange. We show that the antiferromagnetic (AF) rung coupling destroys the long-range order and eventually makes the systems equivalent to the AF s=1/2 Heisenberg chain. We study the crossover from the weak- to strong-coupling regime by different methods, particularly by comparing the results of the spin-wave theory and the bosonization approach. We argue that the crossover regime is characterized by the gapless spectrum and nonuniversal critical exponents are different from those in XXZ model.

AB - We study two similar spin ladder systems with the ferromagnetic leg coupling. The first model includes two sorts of spins s=1/2 and 1, and the second model comprises only s=1/2 legs coupled by a "triangular" rung exchange. We show that the antiferromagnetic (AF) rung coupling destroys the long-range order and eventually makes the systems equivalent to the AF s=1/2 Heisenberg chain. We study the crossover from the weak- to strong-coupling regime by different methods, particularly by comparing the results of the spin-wave theory and the bosonization approach. We argue that the crossover regime is characterized by the gapless spectrum and nonuniversal critical exponents are different from those in XXZ model.

UR - http://www.scopus.com/inward/record.url?scp=13844253584&partnerID=8YFLogxK

U2 - 10.1103/PhysRevB.70.224402

DO - 10.1103/PhysRevB.70.224402

M3 - Article

AN - SCOPUS:13844253584

VL - 70

JO - Physical Review B-Condensed Matter

JF - Physical Review B-Condensed Matter

SN - 1098-0121

IS - 22

ER -