SOLITARY MAGNON LOCALIZATION AND 2-MAGNON BOUND-STATE IN ANTIFERROMAGNET RBFECL3

Introducing the Holstein-Primakoff transformation, the coherent-slate ansatz, and the time-dependent variation principle, two partial differ ential equations of motion from the Hamiltonian are obtained. Employin g the method of multiple scales, these equations are reduced to envelo pe function equations and the amplitude function satisfying a nonlinea r Schrodinger equation is found. Using the inverse scattering transfor mation, single, two, and N solition solutions and the gap soliton are obtained and the solitary excitations in the antiferromagnet RbFeCl3 a re investigated.