相关论文: Density of Neutral Solitons in Weakly Disordered P…
In this letter, we study the effects of weak off-diagonal disorder on conjugated polymers with a doubly degenerate ground-state. We find that disorder induces a finite density of neutral solitons in the lattice dimerization of a polymer…
We show that weak off-diagonal disorder in degenerate ground state conjugated polymers results in a finite density of randomly positioned kinks (solitons and antisolitons) in the lattice dimerization. For realistic values of the disorder,…
We study the (spin-)Peierls transition in quasi-one-dimensional disordered systems, treating the lattice classically. The role of kinks, induced thermally and by disorder, is emphasized. For weak interchain interaction the kinks destroy the…
We investigate the occurrence of singlet bound states in the Raman spectrum of dimerized spin 1/2 chains by Exact Diagonalization and Density Matrix Renormalization Group techniques. We predict that several bulk $\delta$-peaks could be…
We use the Density Matrix Renormalization Group method to study a one-dimensional chain with Peierls electron-phonon coupling, which describes the modulation of the electron hopping by lattice distortions. We demonstrate that this system is…
We extend previous work to consider the effect of the soliton on the density of states and conductivity of quasi-one-dimensional Peierls systems with quantum lattice fluctuations, modeled by a random static disorder. Two features have been…
We consider a chain of atoms that are bound together by a harmonic force. Spin-1/2 electrons that move between neighboring chain sites (H\"uckel model) induce a lattice dimerization at half band filling (Peierls effect). We supplement the…
A model of disordered spin-Peierls system is considered, where domain walls are randomly distributed as a telegraph noise. For this realization of the disorder in an XX spin chain, we calculate exactly the density of states as well as…
A simple intuitive picture of spin-Peierls antiferromagnets arises from regarding the elementary excitations as S=1/2 solitons. In a strictly one-dimensional system these excitations are assumed not to form bound-states and to be repelled…
It has been suggested that the metal-insulator transitions in a number of spinel materials with partially-filled t_2g d-orbitals can be explained as orbitally-driven Peierls instabilities. Motivated by these suggestions, we examine…
We investigate the conventional tight-binding model of $L$ $\pi$-electrons on a ring-shaped mol\-e\-cule of $L$ atoms with nearest neighbor hopping. The hopping amplitudes, $t(w)$, depend on the atomic spacings, $w$, with an associated…
We investigate the effects of disorder on Frenkel excitons in disordered conjugated polymers with allowed rotations about single bonds. In these materials, the principal effect of the disorder is to modify the transfer integrals appearing…
The introduction of modified bond-defects in spin-Peierls systems is investigated in a model of antiferromagnetic Heisenberg spin chains coupled to adiabatic phonons. Generically, new low-energy magnetic or non-magnetic excitations appear…
We study the magnetic properties of a frustrated Heisenberg spin chain with a dynamic spin-phonon interaction. By Lanczos diagonalization, preserving the full lattice dynamics, we explore the non-adiabatic regime with phonon frequencies…
Charge and spin-Peierls instabilities in quarter-filled (n=1/2) compounds consisting of coupled ladders and/or zig-zag chains are investigated. Hubbard and t-J models including local Holstein and/or Peierls couplings to the lattice are…
We study the magnetic response due to neutral solitons induced by disorder in polymer materials. We account for interchain interactions, which, if sufficiently strong, result in a bond-ordered phase, in which the neutral solitons are bound…
The electronic properties of quarter-filled organic materials showing spin-Peierls transition are investigated theoretically. By studying the one-dimensional extended Peierls-Hubbard model analytically as well as numerically, we find that…
Quasi-one-dimensional spin-Peierls and spin-ladder systems are characterized by a gap in the spin-excitation spectrum, which can be modeled at low energies by that of Dirac fermions with a mass. In the presence of disorder these systems can…
The discrete static properties of a class of deformable double-well potential models are investigated. The Peierls-stress potential of the models is explicitely given. Numerical analysis of the equation of motion reveal different soliton…
Motivated to understand the phonon spectrum renormalization in the ground state of the half-filled SSH model, we use the Born-Oppenheimer approximation together with the harmonic approximation to evaluate the all-to-all real-space ionic…