Soliton lattices in the incommensurate spin-Peierls phase: Local distortions and magnetizations

It is shown that nonadiabatic fluctuations of the soliton lattice in the sp in-Peierls system CuGeO3 lead to an important reduction of the NMR hue widt hs. These fluctuations are the zero-point motion of the massless phasonic e xcitations. Furthermore, we show that the discrepancy of x-ray and NMR soli ton widths can be understood as the difference between a distortive and a m agnetic width. Their ratio is controlled by the frustration of the spin sys tem. By this work, theoretical and experimental results can be reconciled i n two important points. [S0163-1829(99)04134-X].