Wall dynamics near the commensurate-incommensurate transition in three-dimensional uniaxial compounds

The authors investigate the inelastic diffusion spectrum one may expect from fluctuating domain walls in the vicinity of the incommensurate-commensurate transition in a 3D uniaxial compound. The diffusion function exhibits a central peak, the width and height of which vary with temperature near the transition. The latter variation is due to the interwall interaction which governs the wall dynamics. They also study the structure factor for quasi-elastic scattering. They find that it contains two terms, one with a usual Debye-Waller factor and one with a Debye-Waller factor that diverges at the commensurability transition.