Yang, SJ (reprint author), Beijing Normal Univ, Dept Phys, Beijing 100875, Peoples R China.
; Yang Shi-Jie] Beijing Normal Univ, Dept Phys, Beijing 100875, Peoples R China
; [Yang Shi-Jie] Chinese Acad Sci, Inst Theoret Phys, State Key Lab Theoret Phys, Beijing 100190, Peoples R China
We investigate a kind of solitons in the two-component Bose-Einstein condensates with axisymmetric configurations in the R-2 x S-1 space. The corresponding topological structure is referred to as Hopfion. The spin texture differs from the conventional three-dimensional (3D) skyrmion and knot, which is characterized by two homotopy invariants. The stability of the Hopfion is verified numerically by evolving the Gross-Pitaevskii equations in imaginary time.