The Hall (R H) and bend (R B) resistances of a graphene Hall bar structure containing a pn-junction are calculated when in the ballistic regime. The simulations are done using the billiard model. Introducing a pn-junction-dividing the Hall bar geometry in two regions-leads to two distinct regimes exhibiting very different physics: (1) both regions are of n-type and (2) one region is n-type and the other p-type. In regime (1), a Hall plateau-an enhancement of the resistance-appears for R H. On the other hand, in regime (2), we found a negative R H, which approaches zero for large B. The bend resistance is highly asymmetric in regime (2) and the resistance increases with increasing magnetic field B in one direction while it reduces to zero in the other direction.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)