Bond-order wave phase, spin solitons and thermodynamics of a frustrated linear spin-1/2 Heisenberg antiferromagnet

Abstract

The linear spin-1/2 Heisenberg antiferromagnet with exchanges $J_1$, $J_2$ between first and second neighbors has a bond-order wave (BOW) phase that starts at the fluid-dimer transition at $J_2/J_1=0.2411$ and is particularly simple at $J_2/J_1=1/2$. The BOW phase has a doubly degenerate singlet ground state, broken inversion symmetry and a finite energy gap $E_m$ to the lowest triplet state. The interval $0.4<J_2/J_1<1.0$ has large $E_m$ and small finite size corrections. Exact solutions are presented up to $N=28$ spins with either periodic or open boundary conditions and for thermodynamics up to $N=18$. The elementary excitations of the BOW phase with large $E_m$ are topological spin-1/2 solitons that separate BOWs with opposite phase in a regular array of spins. The molar spin susceptibility ${\chi }_M(T)$ is exponentially small for $T\ll E_m$ and increases nearly linearly with $T$ to a broad maximum. $J_1$, $J_2$ spin chains approximate the magnetic properties of the BOW phase of Hubbard-type models and provide a starting point for modeling alkali-TCNQ salts.

10 pages, 12 figures

References in corpus (5)

• Phase diagram of the one-dimensional half-filled extended Hubbard model
• Dimerization in a half-filled one-dimensional extended Hubbard model
• Functional Renormalization Group Analysis of the Half-filled One-dimensional Extended Hubbard Model
• The Half-Filled One-Dimensional Extended Hubbard Model: Phase diagram and Thermodynamics
• Tuning the bond order wave (BOW) phase of half-filled extended Hubbard models

Cited by in corpus (10)

• Multipolar phase in frustrated spin-1/2 and 1 chains
• Spin parity and broken symmetry in finite spin-1/2 chains with frustrated exchange: quantum transition from high to low spin
• Modeling the spin-Peierls transition of spin-$1/2$ chains with correlated states: $J_1-J_2$ model, CuGeO${}_3$ and TTF-CuS${}_4$C${}_4$(CF${}_3$)${}_4$
• Magnetic susceptibility of alkali-TCNQ salts and extended Hubbard models with bond order and charge density wave phases
• Bond order wave (BOW) phase of the extended Hubbard model: Electronic solitons, paramagnetism, coupling to Peierls and Holstein phonons
• Quantum phases of spin-1 system on 3/4 and 3/5 skewed ladders
• Quantum phase transition in skewed ladders: an entanglement entropy and fidelity study
• Revealing the topological nature of the bond order wave in a strongly correlated quantum system
• Frustrated mixed-spin ladders: Evidence for a bond order wave phase between rung-singlet and Haldane phases
• Quantum Phase Transitions in Skewed Ladder Systems