Fractional fermions induced by spatially varying Zeeman fields

• Fractional fermions (FFs) can be induced by spatially varying Zeeman fields.
• Period of the field should be commensurate with Rashba spin orbit length.
• Emergence of FFs has no requirements on detailed profiles of the field.

We investigate a one dimensional Rashba system in presence of a spatially varying Zeeman field and show that fractional fermions (FFs) originally occurring in Jackiw–Rebbi model can be induced. Chiral symmetry protected FFs, being a characterization of soliton states carrying fractional charge ±e/2±e/2, may emerge in the middle of band gaps when the period of the Zeeman field is a multiple of a Rashba dependent quantity. Our results also demonstrate that the shape of the non-uniform field is less important in producing chiral FFs, comparing to its period. In the end, we distinguish chiral FFs from those zero mode FFs breaking chiral symmetry and give several examples.