IFLP   13074
INSTITUTO DE FISICA LA PLATA
Unidad Ejecutora - UE
artículos
Título:
Phase diagram study of a dimerized spin-S zig-zag ladder
Autor/es:
C. A. LAMAS; M. MATERA
Revista:
JOURNAL OF PHYSICS CONDENSED MATTER
Editorial:
IOP PUBLISHING LTD
Referencias:
Lugar: Londres; Año: 2014 vol. 26 p. 326004 - 326018
ISSN:
0953-8984
Resumen:
The phase diagram of a frustrated spin-S zigzag ladder is studied through different numerical and analytical methods. We show that for all S, there is a family of Hamiltonians for which a full dimerized state is an exact ground state of the Hamiltonian, being the Majumdar-Ghosh point a particular case. We show that the system presents a transition between a dimerized phase to a N\'eel-like phase for S=1/2, but spiral phases can appear for larger S. The phase diagram is characterized by means of a generalization of the usual Mean Field Approximation (MFA) treatment, consisting on take the strongest coupled sites as the unit cell. The gap and the excitation spectrum is analyzed through the Random Phase Approximation (RPA). Also, a perturbative treatment to obtain the critical points is discussed. Comparisons of the results with numerical methods like DMRG are also presented.