scholarly journals COMPETING PHASES IN SPIN-½ J1-J2 CHAIN WITH EASY-PLANE ANISOTROPY

2011 ◽  
Vol 25 (12n13) ◽  
pp. 901-908 ◽  
Author(s):  
MASAHIRO SATO ◽  
SHUNSUKE FURUKAWA ◽  
SHIGEKI ONODA ◽  
AKIRA FURUSAKI
Keyword(s):  
Phase Diagram ◽  
Ground State ◽  
Nearest Neighbor ◽  
Luttinger Liquid ◽  
Rich Variety ◽  
Narrow Region ◽  
Chiral Phases ◽  
Liquid Phases ◽  
Plane Anisotropy ◽  
Xxz Chain

We summarize our theoretical findings on the ground-state phase diagram of the spin-½ XXZ chain having competing nearest-neighbor (J1) and antiferromagnetic next-nearest-neighbor (J2) couplings. Our study is mainly concerned with the case of ferromagnetic J1, and the case of antiferromagnetic J1 is briefly reviewed for comparison. The phase diagram contains a rich variety of phases in the plane of J1/J2 versus the XXZ anisotropy Δ: vector-chiral phases, Néel phases, several dimer phases, and Tomonaga–Luttinger liquid phases. We discuss the vector-chiral order that appears for a remarkably wide parameter space, successive Néel-dimer phase transitions, and an emergent nonlocal string order in a narrow region of ferromagnetic J1 side.

scholarly journals Entanglement perturbation theory for infinite quasi-1D quantum systems

2015 ◽  
Vol 29 (07) ◽  
pp. 1550042 ◽  
Author(s):  
Lihua Wang ◽  
Sung Gong Chung
Keyword(s):  
Phase Diagram ◽  
Perturbation Theory ◽  
Nearest Neighbor ◽  
Quantum Systems ◽  
Easy Plane ◽  
Heisenberg Chain ◽  
The Third ◽  
Plane Anisotropy ◽  
Improved Accuracy

We develop entanglement perturbation theory (EPT) for infinite Quasi-1D quantum systems. The spin-1/2 Heisenberg chain with ferromagnetic nearest neighbor (NN) and antiferromagnetic next nearest neighbor (NNN) interactions with an easy-plane anisotropy is studied as a prototypical system. The obtained phase diagram is compared with a recent prediction [Phys. Rev. B 81, 094430 (2010)] that dimer and Néel orders appear alternately as the XXZ anisotropy Δ approaches the isotropic limit Δ = 1. The first and second transitions (across dimer, Néel and dimer phases) are detected with improved accuracy at Δ ≈ 0.722 and 0.930. The third transition (from dimer to Néel phases), previously predicted to be at Δ ≈ 0.98, is not detected at this Δ in our method, strongly indicating that the second Néel phase is absent.

GROUND STATE OF THE 2D EXTENDED HUBBARD MODEL WITH MORE THAN NEAREST-NEIGHBOR INTERACTIONS

2012 ◽  
Vol 26 (29) ◽  
pp. 1250156 ◽  
Author(s):  
S. HARIR ◽  
M. BENNAI ◽  
Y. BOUGHALEB
Keyword(s):  
Phase Diagram ◽  
Hubbard Model ◽  
Ground State ◽  
State Energy ◽  
Nearest Neighbor ◽  
Finite Size ◽  
Square Lattice ◽  
Extended Hubbard Model ◽  
Eigenvalues And Eigenvectors ◽  
Repulsion Energy

We investigate the ground state phase diagram of the two dimensional Extended Hubbard Model (EHM) with more than Nearest-Neighbor (NN) interactions for finite size system at low concentration. This EHM is solved analytically for finite square lattice at one-eighth filling. All eigenvalues and eigenvectors are given as a function of the on-site repulsion energy U and the off-site interaction energy Vij. The behavior of the ground state energy exhibits the emergence of phase diagram. The obtained results clearly underline that interactions exceeding NN distances in range can significantly influence the emergence of the ground state conductor–insulator transition.

EFFECTS OF THE NEXT-NEAREST-NEIGHBOR HOPPING IN OPTICAL LATTICES

2008 ◽  
Vol 22 (01) ◽  
pp. 33-44 ◽  
Author(s):  
YUN'E GAO ◽  
FUXIANG HAN
Keyword(s):  
Phase Diagram ◽  
Hubbard Model ◽  
Ground State Energy ◽  
Ground State ◽  
Optical Lattices ◽  
State Energy ◽  
Nearest Neighbor ◽  
Three Dimensional ◽  
Dispersion Relations ◽  
Insulating Phase

Introducing the next-nearest-neighbor hopping t′ into the Bose–Hubbard model, we study its effects on the phase diagram, on the ground-state energy, and on the quasiparticle and quasihole dispersion relations of the Mott insulating phase in optical lattices. We have found that a negative value of t′ enlarges the Mott-insulating region on the phase diagram, while a positive value of t′ acts oppositely. We have also found that the effects of t′ are dependent on the dimensionality of optical lattices with its effects largest in three-dimensional optical lattices.

scholarly journals Phase Diagram ofS=1 XXZ Chain with Next-Nearest-Neighbor Interaction

2005 ◽  
Vol 74 (5) ◽  
pp. 1544-1551 ◽  
Author(s):  
Takahiro Murashima ◽  
Keigo Hijii ◽  
Kiyohide Nomura ◽  
Takashi Tonegawa
Keyword(s):  
Phase Diagram ◽  
Nearest Neighbor ◽  
Neighbor Interaction ◽  
Xxz Chain

SPIN GAPLESS BOND-ORDERED PHASE IN THE EXTENDED HUBBARD CHAIN WITH SPIN-DEPENDENT REPULSION

2011 ◽  
Vol 25 (27) ◽  
pp. 3555-3568 ◽  
Author(s):  
HANQIN DING ◽  
JUN ZHANG
Keyword(s):  
Phase Diagram ◽  
Renormalization Group ◽  
Weak Coupling ◽  
Nearest Neighbor ◽  
Density Wave ◽  
Spin Density Wave ◽  
Extended Hubbard Model ◽  
Weak Coupling Regime ◽  
One Dimensional ◽  
Plane Anisotropy

Using the field theoretical bosonization and renormalization group techniques, we analytically study quantum phase diagram of a one-dimensional half-filled extended Hubbard model with on-site (U) and spin-dependent nearest-neighbor interactions (V⊥, V‖) in the weak coupling regime. In the case of easy-plane anisotropy (V⊥ > V‖) and at V‖ < U/2, the existence of bond-ordered spin-density-wave phase, corresponding to spin gapless transverse magnetization located on bonds (BSDW±) is shown.

THEORETICAL ANALYSIS OF ADSORBATE-INDUCED ROW-TYPE ALIGNMENTS ON THE FCC(110) SURFACE

1999 ◽  
Vol 06 (05) ◽  
pp. 699-704 ◽  
Author(s):  
K. YASUTANI ◽  
M. KABURAGI ◽  
M. KANG
Keyword(s):  
Phase Diagram ◽  
Theoretical Analysis ◽  
Ground State ◽  
Nearest Neighbor ◽  
Comparison Method ◽  
Model Structure ◽  
Two Dimensional ◽  
Ground State Phase Diagram ◽  
Interaction Regime ◽  
Beg Model

The structures of adsorbate-induced row-type alignments of the FCC(110) surface are analyzed using the two-dimensional Blume–Emmery–Griffiths (BEG) model with the nearest-neighbor (NN) and the next-nearest-neighbor (NNN) interactions. The ground state phase diagram in whole regimes of interactions is determined by the energy comparison method. Comparing the results of ground state analysis with experimentally observed structures of the O/Rh(110) and O/Pd(110), we determine the interaction regimes for these systems. From the thus determined interaction regime, we propose the model structure in the c(2 × 6) phase of the O/Pd(110).

Ground state of an Ising-type spin-1/2 chain with competing interactions

2001 ◽  
Vol 79 (11-12) ◽  
pp. 1581-1585 ◽  
Author(s):  
T Tonegawa ◽  
H Matsumoto ◽  
T Hikihara ◽  
M Kaburagi
Keyword(s):  
Phase Diagram ◽  
Ground State ◽  
Nearest Neighbor ◽  
Intermediate Phase ◽  
Group Method ◽  
Density Matrix Renormalization Group ◽  
Competing Interactions ◽  
Density Matrix Renormalization ◽  
Diagonalization Method ◽  
Exact Diagonalization Method

The ground state of an Ising-type spin-1/2 chain with ferromagnetic bond-alternating nearest-neighbor and anti-ferromagnetic uniform next-nearest-neighbor interactions is studied by using the exact-diagonalization method and the density-matrix renormalization-group method. The Hamiltonian describing the system is expressed as H = – Σi h2i–1,2i – J1 Σi h2i,2i+1 + J2 Σi hi,i+2 with hi,i' = γ(Six Si'x + Siy Si'y) + Siz Si'z, where J1 [Formula: see text] 0, J2 [Formula: see text] 0, and 1 > γ [Formula: see text] 0. Special attention is paid to the ground-state phase diagram on the J1 versus J2 plane for a given value of γ. The phase diagram is composed of the ferromagnetic, intermediate, and up-up-down-down phases, the intermediate phase being characterized by its magnetization, which takes finite but unsaturated values. The phase diagram obtained for γ = 0.5 shows that the region of the intermediate phase for a given value of J1 is widest when J1 = 1.0 and becomes narrower rather rapidly as J1 decreases or increases from 1.0. The J2-dependence of the ground-state magnetization for γ = 0.5 and J1 = 0.85 is also discussed. PACS Nos.: 75.10Jm, 75.40Mg

Sign in / Sign up

Export Citation Format

Share Document