Quasiparticle spectrum and thermodynamics of φ solitons (discommensurations) in the charge-density-wave state

The quasiparticle spectrum associated with a soliton (discommensuration) in the quasi-one-dimensional charge-density-wave state is determined theoretically. Making use of the quasiparticle spectrum, we calculate the charge and the entropy associated with a soliton. We find that in the temperature region λ/NT/Δ1, the charge and the entropy of a soliton per chain are given by Q=(2e/N)[1-2βΔK1(βΔ)] and Sφ=(4λ/πN2)(βΔ)3K0 (βΔ), respectively, where Δ is the quasiparticle energy gap, β=1/T, N is the degree of commensurability, λ10-2 is a small parameter, and Kn(z) are modified Bessel functions.