Band effect: A possible mechanism for large magnetoresistance in nonmagnetic materials

Motivated by a recently observed unusual magnetoresistance in sliver chalcogenides, we propose a mechanism for large magnetoresistance in nonmagnetic materials. We show that the Zeeman splitting can play a very important role in MR under certain conditions. In general, the electron density of states can be divided into two parts, one for spin-up electrons and the other for spindown. The two parts will shift against each other in an external magnetic field due to the Zeeman effect, leading to a substantial change in the effective carrier density when the original Fermi level is near the edge of the band and the Lande factor g of electrons is large such that the electron density of states at the Fermi level is sensitive to the external magnetic field.