Adiabatic-antiadiabatic crossover in a spin-Peierls chain

R. Citro, E. Orignac, T. Giamarchi

We consider an XXZ spin-1/2 chain coupled to optical phonons with non-zero frequency ${\omega }_0$. In the adiabatic limit (small ${\omega }_0$), the chain is expected to spontaneously dimerize an…