Related papers: Staggered dimer order in S=1/2 quantum spin ladder…
The magnetization process of the $S$=1/2 antiferromagnetic spin ladder with the four-spin cyclic exchange interaction at T=0 is studied by the exact diagonalization of finite clusters and size scaling analyses. It is found that a…
We present a theoretical study of the magnetic phase diagram of the frustrated coupled ladder structure realized recently in several materials. This system displays a nondegenerate spin-gap state in the dimer limit and an infinitely…
The ground state properties and phase diagram of the bilayer square-lattice Heisenberg model are studied in a broad parameter space of intralayer exchange couplings, assuming an antiferromagnetic coupling between constituent layers. In the…
We have studied the phase diagram of the one dimensional XXZ model with Dzyaloshinskii-Moriya (DM) interaction. We have applied the quantum renormalization group (QRG) approach to get the stable fixed points, critical point and the scaling…
We study the phase diagram of coupled spin-1/2 chains with bilinear and (chiral) three-spin exchange interactions in a magnetic field. The model is soluble on a one-parametric line in the space of coupling constants connecting the limiting…
Nematic order is an exotic property observed in several strongly correlated systems, such as the iron-based superconductors. Using large-scale density matrix renormalization group (DMRG) techniques, we study at zero-temperature the nematic…
The S=2 Heisenberg antiferromagnet on the orthogonal dimer lattice is studied. The edges of the exact dimer and Neel-ordered phases in the ground state of the system are examined by the numerical diagonalization method. Our present results…
The effect of antiferromagnetic interchain coupling in alternating spin (1,1/2) chains is studied by mean of spin wave theory and density matrix renormalization group(DMRG). Two limiting cases are investigated, the two-leg ladder and its…
We investigate an asymmetric zig-zag spin ladder with different exchange integrals on both legs using bosonization and renormalization group. When the leg exchange integrals and frustration both are sufficiently small, renormalization group…
We study a model of two-dimensional interacting monomers which has two symmetric absorbing states and exhibits two kinds of phase transition; one is an order-disorder transition and the other is an absorbing phase transition. Our focus is…
Magnetoelectric effect of the spin-1/2 Heisenberg-Ising ladder in a presence of the external electric and magnetic fields is rigorously examined by taking into account Katsura-Nagaosa-Balatsky mechanism. It is shown that the applied…
We investigate the spatially anisotropic square lattice quantum antiferromagnet. The model describes isotropic spin-1/2 Heisenberg chains (exchange constant J) coupled antiferromagnetically in the transverse (J_\perp) and diagonal…
We apply the twisted order parameter (TOP) for dimerized quantum spin ladders to locate the critical phases that separate gapped phases representing quantum spin liquids of various types. Using the DMRG, method we find that the TOP is a…
Using the density-matrix renormalization-group algorithm (DMRG) and a finite-size scaling analysis, we study the properties of the one-dimensional completely-anisotropic spin-1/2 XYZ model with Dzyaloshinsky-Moriya (DM) interactions. The…
We investigate the isotropic two-leg S=1/2 ladder with general bilinear and biquadratic exchange interactions between spins on neighboring rungs, and determine the Hamiltonians which have a matrix product wavefunction as exact ground state.…
We study the ground state properties of one-dimensional XXZ model with next-nearest neighbor coupling alpha and anisotropy Delta. We find the direct transition between the ferromagnetic phase and the spontaneously dimerized phase. This is…
The effect of a ring exchange on doped two-leg ladders is investigated combining exact diagonalization (ED) and density matrix renormalization group (DMRG) computations. We focus on the nature and weights of the low energy magnetic…
We examine a chain of periodic arrays of 4 quantum spins with magnitudes of 1/2, 1, 3/2 and 1. There are four kinds of nearest-neighbour exchange parameters among them. We choose two independent parameters for concreteness: one represents…
We investigate the phase diagram of the anisotropic spin-1/2 triangular lattice antiferromagnet, with interchain diagonal exchange J' much weaker than the intrachain exchange J. We find that fluctuations lead to a competition between…
We investigate the ground state competition at the transition from the spin unpolarized to spin ordered phase at filling factor $\nu=2/3$ in single layer heterostructure and at $\nu=2$ in double layer quantum well. To trace the quantum Hall…