Negative Interlayer Magnetoresistance and Zero-Mode Landau Level in Multilayer Dirac Electron Systems

Abstract

The interlayer magnetotransport has been considered in multilayer Dirac electron systems, in which two-dimensional electron layers with Dirac-cone dispersion stack with weak interlayer coupling. Under magnetic fields, one Landau level (zero-mode) always appears at the contact point of Dirac cones, and tunneling between the zero-modes on neighboring layers dominates interlayer transport in multilayer systems. The increase of zero-mode degeneracy causes strong negative magnetoresistance. Spin splitting of the zero-mode could change the negative magnetoresistance to the positive one in high magnetic fields and low temperatures. The magnetotransport features observed in an organic conductor α-(BEDT-TTF) 2 I 3 are discussed based on the present model.