New Mechanism of Magnetoresistance in Bulk Semiconductors: Boundary   Condition Effects
  We consider the electronic transport in bounded semiconductors in the presence of an external magnetic field. Taking into account appropriate boundary conditions for the current density at the contacts, a change in the magnetoresistance of bulk semiconductors is found as compared with the usual theory of galvanomagnetic effects in boundless media. New mechanism in magnetoresistance connected with the boundary conditions arises. In particular, even when the relaxation time is independent of the electron energy, magnetoresistance is not vanish. 
G. Gonzalez de la Cruz, Yu. G. Gurevich (1), V. V. Prosentsov (2) ((1)   http://www.fis.cinvestav.mx/~gurevich/, Centro de I...