Short-range order in spin density wave antiferromagnets with chemical dimerization

The spin density wave model in a quasi-one-dimensional itinerant antiferrom agnet with staggered potential at finite temperature is studied. Only short -range ordering exists in this system above the Neel temperature. The local -band theory of spin fluctuations is developed to calculate the spin densit y wave amplitude and the effective exchange integral. The one-electron spec trum and magnon spectrum are obtained in the short-range ordering regime. ( C) 1998 American Institute of Physics. [S1063-7761(98)01310-9].