Bag formation in quantum Hall ferromagnets - art. no. 075310

Charged skyrmions or spin textures in the quantum Hall ferromagnet at a fil ling factor nu = 1 are reinvestigated using the Hartree-Fock method in the lowest-landau-level approximation. It is shown that a single Slater determi nant with minimum energy in the unit charge sector is always of the hedgeho g form. It is observed that the magnetization vector's length deviates loca lly from unity, i.e., a bag is formed which accommodates the excess charge. In terms of a gradient expansion for extended spin textures, an O(3) type of effective action is presented, which takes bag formation into account.