2009/12/31 by Toshiya Hikihara, Oleg A. Starykh · 1 citation
Mathematics · Physics and Astronomy · #Advanced Condensed Matter Physics #Antiferromagnetism #Condensed matter physics #Degeneracy (biology) #Density matrix renormalization group #Diagonal #Ferromagnetism #Frustration #Hamiltonian (control theory) #Mathematics #Phase (matter) #Phase diagram #Physics #Physics of Superconductivity and Magnetism #Quantum many-body systems #Quantum mechanics #Renormalization group #cond-mat.stat-mech #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.81.064432
published as Phys. Rev. B 81, 064432 (2010) · 12 pages, 12 figures, 1 Table. v2: version to appear in Phys. Rev. B
arxiv created 2010/02/24 · openalex publication_date 2010/02/25 · arxiv updated 2010/04/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We revisit the phase diagram of the frustrated spin-1/2 ladder with two competing interchain antiferromagnetic exchanges, rung coupling J_\ensuremath⊥ and diagonal coupling J_\ifmmode×\else\texttimes\fi. We suggest, based on the accurate renormalization-group analysis of the low-energy Hamiltonian of the ladder, that marginal interchain current-current interaction plays central role in destabilizing previously predicted intermediate columnar dimer phase in the vicinity of classical degeneracy line J_\ensuremath⊥=2J_\ifmmode×\else\texttimes\fi. Following this insight we then suggest that changing these competing interchain exchanges from the previously considered antiferromagnetic to the ferromagnetic ones eliminates the issue of the marginal interactions altogether and dramatically expands the region of stability of the columnar dimer phase. This analytical prediction is convincingly confirmed by the numerical density-matrix renormalization-group and exact-diagonalization calculations as well as by the perturbative calculation in the strong rung-coupling limit. The phase diagram for ferromagnetic J_\ensuremath⊥ and J_\ifmmode×\else\texttimes\fi is determined.