Spin dynamics and the delocalization of hole quasiparticles

Hole motion through a Heisenberg antiferromagnet is examined using a restricted set of spin configurations to describe the spin distortion around the hole. The hole induces spin singlets, not ferromagnetism at the (magnetic) Brillouin-zone boundary. An inherently many-particle band structure is found. Each band is associated with a different spin distortion around the hole. Most of the bands are found dispersionless, in agreement with photoemission data from the high-temperature superconducting cuprates.