Phase Diagram of the Spin-\((1)/(2)\) Bond-Alternating Two-Leg Ladder

2003/05/15 by Masaaki Nakamura, Takahiro Yamamoto, Kôichirô Ide +1
Physics and Astronomy · #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Quantum many-body systems

paper · doi:10.1143/jpsj.72.1022

Abstract

We study phase transition between two topologically different gapped states in the spin-1/2 bond-alternating two-leg Heisenberg ladder by investigating string order parameters and the level-crossing method based on the exact diagonalization. We determine the phase diagram on the plane of the bond-alternation δ and the rung-leg coupling ratio J ⊥ / J , and conclude that the boundary is given as J ⊥ / J ∝δ 2/3 in the weak coupling region J ⊥ / J , δ≪1.

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